mm-82 === Here m varies and you question that possibility for the a's to be| continuous everywhere. Now what do you see in those equations Keith| Ramsay?You say whether a1, a2, and a3 are continuous is irrelevant, so if youwant to you, feel free to skip the following explanation for why theycan't all three be continuous and defined everywhere. The explanationcan be made more precise if you don't believe me.It's called monodromy. It's related to Galois theory! But it'smore geometric.At m=0, two of the a's are the same. For m near 0, but not exactly at0, two of them are close together, while the third is farther away,staying close to the value it has at 0.If we take m on a path around 0, going in small steps, because the a'sare continuous they would have also to change in small steps. What isinteresting is what happens to them when m is brought back to where itstarted: those two a's are forced to exchange places with each other.But that would contradict the fact that they have the values they doat the original m close to 0, and that they're continuous, and defined for all algebraic integers m. (It's possible to step along such a pathstepping only on algebraic integers, because there are algebraicintegers close to any point on the complex plane.)It's easier to see in the case of x^2-m = (x-b1)(x-b2), so that b1 andb2 are the two complex square roots of m (b2=-b1). If we take m in aloop around m=0, then its two square roots exchange places with eachother. They also go around 0 in the complex plane, but half as fast asm does. So for b1 and b2 both to be continuous is impossible. The usual? is to decide on a place to cut the plane, and make them switch asthey cross the cut.I would have to do a more careful calculation to be sure that the thirda in the example from the paper can't be continuous either, becauseon a different path it changes place with one of the first two, but Ithink that's also true. One would have to look carefully at the way thea's change going to one of the other values of m where two a's coincide,and I don't see any way to make the calculation simple yet.[...]| Hmmm...maybe it'd help to consider the other g's now that you bring| them up.| | You have to remember that I can consider P(m)/f^2, and then you have| | P(m)/f^2 = g_1 g_2 g_3/f^2| | and I'm merely noting the consequence of P(0)/f^2 being coprime to f.Namely, that the factor of f in g_1 must go away. Really, the mainquestion I had at this point was what you meant by go away. Dividingg_1 g_2 g_3 by f^2 doesn't necessarily correspond to any operation ong_1, g_2, and g_3 separately. This concept of what factor of f istaken away from g_1 when the product of g_1, g_2, and g_3 is dividedby f^2 hasn't been de?ed.It sounds like (this is a guess) you mean that you want to write acommon re?ement of the two factorizations of P, namely f^2*(P/f^2)and g_1*g_2*g_3. This would be a way to write P as a product ABCDEFwhere AB=g_1, CD=g_2, and EF=g_3, and f^2=ACE, and P/f^2=BDF. Itfurther sounds like by the factor of f in g_1 going away you mean torefer to the factor A in it, which is a common factor of f^2 and g_1.If this is what you mean, you would be considering the product as beingdivided by f^2 by having the factors A,C,E taken out of g_1, g_2, andg_3 separately.If this is so, then one of the main questions is what values thiscommon factor has when m is not 0. I don't see a problem with sayingit's f when m=0, but I also don't see why it shouldn't be a varyingfactor of f as m changes.[...]| > It's looking like the factor going away is supposed to be a factor| > of a_1 in some sense or another. If so, what sense?| | In considering P(m)/f^2 = g_1 g_2 g_3/f^2, I'm ?uring out how that| factor f^2 goes through the g's.| | What I ?d is that it only makes sense if only two of the g's have a| factor of f that is f, but then you're forced out of the ring of| algebraic integers, though it doesn't appear to have happened from| within the argument, which is why that ring is ?I was thinking we knew that two of the a's were 0 at m=0, so that thecorresponding g's were uf there, and hence divisible by f. I don't seehow you plan to apply this to the situation when m is not 0.| > Perhaps it would help if you clari?d and/or con?med a few things.| > When in the paper you write that g1 must have that same factor (of| > f) in general, does in general mean that you're saying the value| > of g1 for each allowed value of m is divisible by f? | | It depends on context. It's like if you have y=2x+1, and consider| various values. Now I see pressure to write that as f(x)=2x+1, but I| don't think it's worth the potential confusion.| | The problem is that though you see m as the key variable, it may in| fact be a *factor* of m that is the true independent variable, which| I'm sure has confused quite a few people. Now it's a measure of your| mathematical ability if you know what I mean there, and let's just say| that I'm not interested in expanding out in a way that leaves *more*| room for confusion.Unfortunately, if the only way that the argument actually works foryou is that in the background, you're implicitly permitting yourselfthis kind of reparametrization, then the thing you have written downisn't a complete proof.Yes, there are clever techniques involving substituting parameters,sometimes used to circumvent the presence of a Galois group ormonodromy, but if you plan to go that route you still need to say whatyou're doing.| >Or do you mean| > something else? Is it a fair paraphrase of the step where you| > introduce a1, a2, and a3, to say that they are three functions from| > the algebraic integers to the algebraic integers, a1(m), a2(m), and| > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for| > every x?| | They're not necessarily functions of m.At some point you need actually to say what kind of thing a1, a2, anda3 are, without leaving any special wriggle room. If treating them asfunctions of m is not quite good enough, then you really need to saywhat they are.| Think about it Keith Ramsay. Sit down, go over what I've given and| think very carefully over just that one point, and maybe, if you're| honestly confused, it'll help you to break through to an| understanding.[...]| Posts should get *shorter* and not longer.Keith Ramsay === > > Here I'm right, and you're wrong, as the *de?ition* of algebraic> integer leads to an incomplete ring, which I prove mathematically.> The trouble is, I'm still not following your logic, just to be able to> see what the great contradiction is.> (a) I have two algebraic integers x and y> (b) I claim that y is a factor of x in the algebraic integersNope. There is no claim that y is a factor as it's *provably* afactor.Rather than deal with the term factor as people get confused, in mypaper Advanced Polynomial Factorization, I have three numbers a_1,a_2, and a_3, and I prove that a_3 is coprime to a factor I call f.You also have that a_1 a_2 a_3 have f^2 as a factor, so proving thata_3 is coprime to f, means that a_1 and a_2 shouldn't be.But there's a contradiction because they don't technically have *any*factors of f, so that means that the de?ition of algebraic integers,with a strict interpretation of the word factor would mean thatneither a_1, a_2, nor a_3 have f as a factor when a_1 a_2 a_3 has f^2as a factor. > (c) But there is no algebraic integer z (=x/y) such that y*z = x> This leads inexorably to the conclusion that the claim in (b) is simply> false. There are *lots* of possible algebraic integers which I can> multiply by *something* to get x, but there are only a few choices that> I can multiply by another algebraic integer to get x, and those are the> factors.You're running in circles.First consider that the de?ition of algebraic integers as the*roots* of monic polynomials with integer coef?ients does notspeci?ally give you any protection from contradiction.The de?ition is over the ?ld of rationals, and it's not clear injust looking at it, if it will give a complete ring.Mathematicians apparently *assumed* it did, and have gone on thatassumption for some time.People seem ?ed on the *de?ition* with the assumption, whenthere's no proof based on the de?ition that the ring is complete.And there can't be such a proof because I've *proven* it's notcomplete, as that de?ition leads to a contradiction.> Basically, I do not see in what sense you can claim that y is a factor> of x without demonstrating the properties of x/y... just being able to> multiply y by something to get x isn't enough to be able to claim that.> And without that claim, the conclusion about incompleteness isn't there.Go to the following link, ?d and read my paper Advanced PolynomialFactorization: http://groups.msn.com/AmateurMathand you will see how you can prove that x has y as a factor.> Perhaps it could help if you could give me a rigorous de?ition of> what you mean by incomplete ring, or conversely complete ring. Is> this a property which is distinct from being, say, closed under> multiplication?Consider c=ab, where ?c' is an algebraic integer, and ?a' is analgebraic integer, but ?b' is not.Now if you include fractions or move to a ?ld like algebraic numbersthat's ok. But I'm talking about ?b' that's not in any way a fractionor fractional.It's like with the ring of evens, and given 6 = 2(3), you have that 3is outside the ring, as in the ring of evens, 2 is NOT a factor of 6.The situation is analogous.Do you understand?James Harris === > [...]> | Here m varies and you question that possibility for the a's to be> | continuous everywhere. Now what do you see in those equations Keith> | Ramsay?> You say whether a1, a2, and a3 are continuous is irrelevant, so if you> want to you, feel free to skip the following explanation for why they> can't all three be continuous and de?ed everywhere. The explanation> can be made more precise if you don't believe me.If I have y=mx+b in the ring of algebraic integers, is y continuous?The ring is algebraic integers, but you're trying to wander off intosomething unrelated to the paper, which I guess is some knowledgeyou're proud to have memorized.But do you *understand* it? > It's called monodromy. It's related to Galois theory! But it's> more geometric.> At m=0, two of the a's are the same. For m near 0, but not exactly at> 0, two of them are close together, while the third is farther away,> staying close to the value it has at 0.> If we take m on a path around 0, going in small steps, because the a's> are continuous they would have also to change in small steps. What is> interesting is what happens to them when m is brought back to where it> started: those two a's are forced to exchange places with each other.My guess is that you have some way to expand on that, and if you do,and it depends on some p-adic interpretation then I will rip you apartby forcing you down to the rigorous and EXACT numbers.You see Mathematics is an in?ite world where your brain can getquite lost, but be proud of itself anyway as it can simply tell itselfthat it's not lost.> But that would contradict the fact that they have the values they do> at the original m close to 0, and that they're continuous, and de?ed> for all algebraic integers m. (It's possible to step along such a path> stepping only on algebraic integers, because there are algebraic> integers close to any point on the complex plane.)Why don't you just quit babbling, solve for the a's, and with thatsolution try to prove your claim?And that's what I mean readers about people who think mathematics is afashion show.Mathematics is an in?ite subject, which forces perfection. Humanbeings, however, have mathematics, which is a ?ite subject made upof what people can discover in a fascinatingly short period of time,and unfortunately, people can also screw up and put errors inmathematics.> It's easier to see in the case of x^2-m = (x-b1)(x-b2), so that b1 and> b2 are the two complex square roots of m (b2=-b1). If we take m in a> loop around m=0, then its two square roots exchange places with each> other. They also go around 0 in the complex plane, but half as fast as> m does. So for b1 and b2 both to be continuous is impossible. The usual> ? is to decide on a place to cut the plane, and make them switch as> they cross the cut.That's an operator problem. That is, in trying to evaluate a valuefor b1 or b2, you use the sqrt() operator, and get lost on itsinherent ambiguity.However for the math there is no such problem as it simply deals withthe value of b1 and b2 at each point. It doesn't think to itself,take the square, ?ure out if it's negative or positive.You, however, can get confused.If you wish to see it in some sense the way the math sees it, use onlygaussian integers for m in your loop that are squares in the ring ofgaussian integers.Try that and report back Keith Ramsay.> I would have to do a more careful calculation to be sure that the third> a in the example from the paper can't be continuous either, because> on a different path it changes place with one of the ?st two, but I> think that's also true. One would have to look carefully at the way the> a's change going to one of the other values of m where two a's coincide,> and I don't see any way to make the calculation simple yet.And you've gone off on a tangent. But as you mention it, I suggestyou go ahead and be *careful* instead of possibly hoping that you canget away with casting doubt.It's not a political discussion Keith Ramsay. You're not on Fox News.> [...]> | Hmmm...maybe it'd help to consider the other g's now that you bring> | them up.> | > | You have to remember that I can consider P(m)/f^2, and then you have> | > | P(m)/f^2 = g_1 g_2 g_3/f^2> | > | and I'm merely noting the consequence of P(0)/f^2 being coprime to f.> Namely, that the factor of f in g_1 must go away. Really, the main> question I had at this point was what you meant by go away. Dividing> g_1 g_2 g_3 by f^2 doesn't necessarily correspond to any operation on> g_1, g_2, and g_3 separately. This concept of what factor of f is> taken away from g_1 when the product of g_1, g_2, and g_3 is divided> by f^2 hasn't been de?ed.That's nonsensical. Now I guess you're questioning the assumptionthat given that g_1 g_2 g_3 have f^2 as a factor, some of the g's musthave some non unit factor in common with f.Well gee, it turns out that *in the ring of algebraic integers* exceptfor at m=0, NONE of the g's share any non unit factors in common withf.It's bizarre; it's wacky; and it shows that the ring of algebraicintegers is incomplete.> It sounds like (this is a guess) you mean that you want to write a> common re?ement of the two factorizations of P, namely f^2*(P/f^2)> and g_1*g_2*g_3. This would be a way to write P as a product ABCDEF> where AB=g_1, CD=g_2, and EF=g_3, and f^2=ACE, and P/f^2=BDF. It> further sounds like by the factor of f in g_1 going away you mean to> refer to the factor A in it, which is a common factor of f^2 and g_1.> If this is what you mean, you would be considering the product as being> divided by f^2 by having the factors A,C,E taken out of g_1, g_2, and> g_3 separately.> If this is so, then one of the main questions is what values this> common factor has when m is not 0. I don't see a problem with saying> it's f when m=0, but I also don't see why it shouldn't be a varying> factor of f as m changes.Yeah, and I gave an example yesterday which should tell you why. P(x) = 2x^2 + 4x + 2 (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2 a_1 a_2 = 2x^2,and I note that when x=0, at *least* one of the a's must equal 0, andfurther note that the constant term of the factor a_1 + 1, which I'llcall g_1 is 1 at that point. Further the factor a_2 + 2 has a factorthat is 2 at that point, and I'll call it g_2.Now then Keith Ramsay, do you question what g_2 will do when x doesnot equal 0?So why do you do it above?Ultimately, you may try and claim that irreducibility over Q is what'spertinent, if so, explain in detail.> [...]> | > It's looking like the factor going away is supposed to be a factor> | > of a_1 in some sense or another. If so, what sense?> | > | In considering P(m)/f^2 = g_1 g_2 g_3/f^2, I'm ?uring out how that> | factor f^2 goes through the g's.> | > | What I ?d is that it only makes sense if only two of the g's have a> | factor of f that is f, but then you're forced out of the ring of> | algebraic integers, though it doesn't appear to have happened from> | within the argument, which is why that ring is ?> I was thinking we knew that two of the a's were 0 at m=0, so that the> corresponding g's were uf there, and hence divisible by f. I don't see> how you plan to apply this to the situation when m is not 0.I've generalized that factors of polynomials can be written as r+c,where r=0, or varies while the polynomial factor varies, and c isconstant and is a factor of the constant term of the polynomial.That's easy to see with something like x+2 as a factor of x^2+3x+2.In the paper I have that as a lemma, with a proof.If anyone had an actual error in the paper, they could simply showfault with the lemma, as it's the key linchpin.Instead I get overlong posts where people bring up tangents, and keepquestioning things that are obvious.Mathematicians are such dweebs.> | > Perhaps it would help if you clari?d and/or con?med a few things.> | > When in the paper you write that g1 must have that same factor (of> | > f) in general, does in general mean that you're saying the value> | > of g1 for each allowed value of m is divisible by f? > | > | It depends on context. It's like if you have y=2x+1, and consider> | various values. Now I see pressure to write that as f(x)=2x+1, but I> | don't think it's worth the potential confusion.> | > | The problem is that though you see m as the key variable, it may in> | fact be a *factor* of m that is the true independent variable, which> | I'm sure has confused quite a few people. Now it's a measure of your> | mathematical ability if you know what I mean there, and let's just say> | that I'm not interested in expanding out in a way that leaves *more*> | room for confusion.> Unfortunately, if the only way that the argument actually works for> you is that in the background, you're implicitly permitting yourself> this kind of reparametrization, then the thing you have written down> isn't a complete proof.Then prove it.There are lots of things that I think about that aren't needed to showa proof, and I don't put them into discussions unless it suits me.Remember, a proof begins with a truth and proceeds by logical steps toa conclusion which then must be true.I only need give that truth in the beginning and proceed by logicalsteps.That you can move deeper into portions in a way that isn't material tothe argument makes the math just a little more fun...well it does forme at least.> Yes, there are clever techniques involving substituting parameters,> sometimes used to circumvent the presence of a Galois group or> monodromy, but if you plan to go that route you still need to say what> you're doing.That is irrelevant. See? I knew that bringing the subject up mightjust distract you.Why don't you focus on the important path of the proof, and not worryabout sideroads?> | >Or do you mean> | > something else? Is it a fair paraphrase of the step where you> | > introduce a1, a2, and a3, to say that they are three functions from> | > the algebraic integers to the algebraic integers, a1(m), a2(m), and> | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for> | > every x?> | > | They're not necessarily functions of m.> At some point you need actually to say what kind of thing a1, a2, and> a3 are, without leaving any special wriggle room. If treating them as> functions of m is not quite good enough, then you really need to say> what they are.You didn't connect back with your own statement, fascinating.I'm repeating myself with that statement, but before you talked ofreparametrization in reply.I fear you are a parrot. You look for key words and then regurgitatebased on something you think is relevant, but you need to THINK.> | Think about it Keith Ramsay. Sit down, go over what I've given and> | think very carefully over just that one point, and maybe, if you're> | honestly confused, it'll help you to break through to an> | understanding.> [...]> | Posts should get *shorter* and not longer.> Keith RamsayAnd I'll reiterate that posts should get shorter and not longer.It's called cutting to the chase, or getting to the nitty-gritty.James Harris === | > [...]| > | Here m varies and you question that possibility for the a's to be| > | continuous everywhere. Now what do you see in those equations Keith| > | Ramsay?| > | > You say whether a1, a2, and a3 are continuous is irrelevant, so if you| > want to you, feel free to skip the following explanation for why they| > can't all three be continuous and de?ed everywhere. The explanation| > can be made more precise if you don't believe me.| | If I have y=mx+b in the ring of algebraic integers, is y continuous?Assuming you mean that m and b are algebraic integers, and y is beinggiven as a function of x, yes.Remember (unlike e.g. the Gaussian integers) the algebraic integersare dense in the complex plane, meaning that any circle, no matterhow small, has algebraic integers inside it. | The ring is algebraic integers, but you're trying to wander off into| something unrelated to the paper, which I guess is some knowledge| you're proud to have memorized.My memory is decent, but nothing to be proud of.No, my main point in bringing this stuff up was to try to convinceyou that de?ing a1, a2, and a3 in such a way that their values atone point are related to their values at other points in a useful way.If my explanation isn't working, ?e, someone will eventually ?da better way of explaining it to you.| > If we take m on a path around 0, going in small steps, because the a's| > are continuous they would have also to change in small steps. What is| > interesting is what happens to them when m is brought back to where it| > started: those two a's are forced to exchange places with each other.| | My guess is that you have some way to expand on that, and if you do,| and it depends on some p-adic interpretation then I will rip you apart| by forcing you down to the rigorous and EXACT numbers.You have a way of being melodramatic when it doesn't make sense.First of all, don't try to hint that I'm prone to pretending that I'mdealing with complex numbers when I'm actually sneakily dealing withp-adic numbers. You're the one who's been dealing with a1, a2, anda3 having indeterminate type.Second, p-adic numbers ARE exact. They're just a different system.It's easier in a lot of ways to be rigorous with them than it isto be rigorous with the real numbers or the complex numbers.Third, you're surely aware that nobody will be ripping anybodyapart or forcing anybody to do anything. People have tried hardto force you down to rigor, for example by telling you what,allegedly, the common factors between 5 and the roots of that cubicare. Doesn't phase you a bit! And you've shown us all how easy it isto be impervious to demands for rigor.| You see Mathematics is an in?ite world where your brain can get| quite lost, but be proud of itself anyway as it can simply tell itself| that it's not lost.on the algebraic integers, when the property I actually needed wascontinuity not only at the algebraic integers, but at all complexnumbers. My mistake was to think that the fact that the algebraicintegers are dense in the plane would be good enough, but it isn't.You might say that the discontinuities can be hidden atnon-algebraic-integer points. There is, for example, a uniquefunction f(z) de?ed on the complex numbers a+bi such thatb <> pi*a, satisfying f(z)^2=z, f(1)=1, and f(-1)=i. It can'tbe extended to the line b=pi*a because it approaches differentlimits on either side of that line (it jumps there) on theside where a,b < 0. If we restrict it to the algebraic integers,then it's continuous (because continuous would mean only continuouson algebraic integers).I'm still saying that the situation with a1, a2 and a3 is analogousto the situation with the two so-called branches of the squareroot multiple-valued function. It's not all that hard to give arigorous proof of what I said about continuous square root functions:Suppose that f(z) is a function on the complex plane having complexvalues, and satisfying f(z)^2=z for all z. The goal is to show thatthis leads to a contradiction. Actually, it's enough to consider iton the circle, which consists of complex numbers of the form e^{it}where t is a real number.Because for each real t, f(e^{it})^2 - e^{it}= (f(e^{it})-e^{it/2})(f(e^{it})+e^{it/2}), we also have thateither f(e^{it}) = e^{it/2} or f(e^{it}) = -e^{it/2}. Denote by Athe set of t satisfying f(e^{it}) = e^{it/2} and by B the set oft satisfying f(e^{it}) = -e^{it/2}. Since e^{it/2} <> 0 for anyreal t, the two sets A and B are disjoint, and I've just shownthat their union is the whole real line.The next thing is to prove that they are both closed sets. A closedset is a set like A which has as an element every complex number zhaving the property that for every epsilon>0, there is an elementof A within epsilon of z. But A and B are the sets of zeros of thecontinuous functions f(e^{it})-e^{it/2} and f(e^{it})+e^{it/2}respectively, and the set of zeros of a continuous function is alwaysclosed. The proof of that is that if g is continuous, and g(z) <> 0,then there exists by the de?ition of continuity a delta > 0 suchthat |g(z')-g(z)|<|g(z)| when |z'-z|0 as well. So if g is continuous and z isn't a zero,then there's a delta>0 such that no other zeros of g come withindelta of z. Conversely, if there are zeros within any delta>0 ofz, then z must also be a zero.Finally, we use a standard result that the real line can't bebroken into two disjoint nonempty sets which are both closed.The standard proof is by the least upper bound principle. If Aand B are the two nonempty closed sets, suppose a is an elementof A and b is an element of B. Without loss of generality, a < b;the proof for b < a is essentially the same. Let a' be the leastupper bound of the elements of A less than b. Because a' is anupper bound, there are no elements of A between a' and b. So forevery delta>0, delta0such that every number within delta of a' is also in B, includingthe open segment from max(a, a'-delta) to a'. That meansmax(a, a'-delta) is a lesser upper bound on A, contradicting thefact that a' was the least upper bound.It follows that one of A or B is empty, and the other is the wholereal line. But that's impossible, since if f(1) = f(e^{0*i}) =e^{0*i/2} = 1 then f(1) = f(e^{2*pi*i}) = -(-1) = -e^{pi*i}= -e^{2*pi*i/2}, and if f(e^{0*i})=-e^{0*i/2} then f(e^{2*pi*i})= e^{2*pi*i/2}. This is where the wraparound comes in; if 0 isin A then 2*pi is in B and vice-versa.So in fact the original assumption that there was such an f wasfalse, Q.E.D.Now, a1 and a2 are not square roots, but they are similar enoughto a constant times the square root of m to make the same type ofargument apply.Keith Ramsay === > | > [...]> | > | Here m varies and you question that possibility for the a's to be> | > | continuous everywhere. Now what do you see in those equations Keith> | > | Ramsay?> | > | > You say whether a1, a2, and a3 are continuous is irrelevant, so if you> | > want to you, feel free to skip the following explanation for why they> | > can't all three be continuous and de?ed everywhere. The explanation> | > can be made more precise if you don't believe me.> | > | If I have y=mx+b in the ring of algebraic integers, is y continuous?> Assuming you mean that m and b are algebraic integers, and y is being> given as a function of x, yes.> Remember (unlike e.g. the Gaussian integers) the algebraic integers> are dense in the complex plane, meaning that any circle, no matter> how small, has algebraic integers inside it.Hmmm...interesting assertion, but what about singularities? > | The ring is algebraic integers, but you're trying to wander off into> | something unrelated to the paper, which I guess is some knowledge> | you're proud to have memorized.> My memory is decent, but nothing to be proud of.That's not what I said, as I assume that no matter what your level ofpride in your memory might be you do actually remember some things.> No, my main point in bringing this stuff up was to try to convince> you that de?ing a1, a2, and a3 in such a way that their values at> one point are related to their values at other points in a useful way.Um, but that is an insinuation that they aren't already rigorouslyde?ed, when in fact they are.> If my explanation isn't working, ?e, someone will eventually ?d> a better way of explaining it to you.That is an irrational statement. Where do you suppose this someoneis?Possibly your memory tells you they're in some potential ?ld?> | > If we take m on a path around 0, going in small steps, because the a's> | > are continuous they would have also to change in small steps. What is> | > interesting is what happens to them when m is brought back to where it> | > started: those two a's are forced to exchange places with each other.> | > | My guess is that you have some way to expand on that, and if you do,> | and it depends on some p-adic interpretation then I will rip you apart> | by forcing you down to the rigorous and EXACT numbers.> You have a way of being melodramatic when it doesn't make sense.> First of all, don't try to hint that I'm prone to pretending that I'm> dealing with complex numbers when I'm actually sneakily dealing with> p-adic numbers. You're the one who's been dealing with a1, a2, and> a3 having indeterminate type.That is false as the a's are determined both in form and type.> Second, p-adic numbers ARE exact. They're just a different system.> It's easier in a lot of ways to be rigorous with them than it is> to be rigorous with the real numbers or the complex numbers.Is that something you have from memory Keith Ramsay?> Third, you're surely aware that nobody will be ripping anybody> apart or forcing anybody to do anything. People have tried hard> to force you down to rigor, for example by telling you what,> allegedly, the common factors between 5 and the roots of that cubic> are. Doesn't phase you a bit! And you've shown us all how easy it is> to be impervious to demands for rigor.That's an appeal to the gallery, which is a logical fallacy.> | You see Mathematics is an in?ite world where your brain can get> | quite lost, but be proud of itself anyway as it can simply tell itself> | that it's not lost.> on the algebraic integers, when the property I actually needed was> continuity not only at the algebraic integers, but at all complex> numbers. My mistake was to think that the fact that the algebraic> integers are dense in the plane would be good enough, but it isn't.> You might say that the discontinuities can be hidden at> non-algebraic-integer points. There is, for example, a unique> function f(z) de?ed on the complex numbers a+bi such that> b <> pi*a, satisfying f(z)^2=z, f(1)=1, and f(-1)=i. It can't> be extended to the line b=pi*a because it approaches different> limits on either side of that line (it jumps there) on the> side where a,b < 0. If we restrict it to the algebraic integers,> then it's continuous (because continuous would mean only continuous> on algebraic integers).>> I'm still saying that the situation with a1, a2 and a3 is analogous> to the situation with the two so-called branches of the square> root multiple-valued function. It's not all that hard to give a> rigorous proof of what I said about continuous square root functions:> Suppose that f(z) is a function on the complex plane having complex> values, and satisfying f(z)^2=z for all z. The goal is to show that> this leads to a contradiction. Actually, it's enough to consider it> on the circle, which consists of complex numbers of the form e^{it}> where t is a real number.> Because for each real t, f(e^{it})^2 - e^{it}> = (f(e^{it})-e^{it/2})(f(e^{it})+e^{it/2}), we also have that> either f(e^{it}) = e^{it/2} or f(e^{it}) = -e^{it/2}. Denote by A> the set of t satisfying f(e^{it}) = e^{it/2} and by B the set of> t satisfying f(e^{it}) = -e^{it/2}. Since e^{it/2} <> 0 for any> real t, the two sets A and B are disjoint, and I've just shown> that their union is the whole real line.Your limitation is in needing the sqrt() operator, but being unable tosimply give the result in general. The math doesn't have that problemas it doesn't need operators, but simply sees the result as it is.For instance, consider (1+sqrt(-3))/2, which is in fact a unit in thering of algebraic integers, but it *looks* nothing like 1, or i,because you have the two operators sqrt() and /.(Purists may note that this algebraic integer cannot be expressedusing only ring operators.)You have no meaningful means of further resolution.But the math sees a number. > The next thing is to prove that they are both closed sets. A closed> set is a set like A which has as an element every complex number z> having the property that for every epsilon>0, there is an element> of A within epsilon of z. But A and B are the sets of zeros of the> continuous functions f(e^{it})-e^{it/2} and f(e^{it})+e^{it/2}> respectively, and the set of zeros of a continuous function is always> closed. The proof of that is that if g is continuous, and g(z) <> 0,> then there exists by the de?ition of continuity a delta > 0 such> that |g(z')-g(z)|<|g(z)| when |z'-z| implies g(z')<>0 as well. So if g is continuous and z isn't a zero,> then there's a delta>0 such that no other zeros of g come within> delta of z. Conversely, if there are zeros within any delta>0 of> z, then z must also be a zero.> Finally, we use a standard result that the real line can't be> broken into two disjoint nonempty sets which are both closed.> The standard proof is by the least upper bound principle. If A> and B are the two nonempty closed sets, suppose a is an element> of A and b is an element of B. Without loss of generality, a < b;> the proof for b < a is essentially the same. Let a' be the least> upper bound of the elements of A less than b. Because a' is an> upper bound, there are no elements of A between a' and b. So for> every delta>0, delta the fact that B is closed, a' is an element of B. On the other> hand, by the fact that A is closed, this means there is a delta>0> such that every number within delta of a' is also in B, including> the open segment from max(a, a'-delta) to a'. That means> max(a, a'-delta) is a lesser upper bound on A, contradicting the> fact that a' was the least upper bound.> It follows that one of A or B is empty, and the other is the whole> real line. But that's impossible, since if f(1) = f(e^{0*i}) => e^{0*i/2} = 1 then f(1) = f(e^{2*pi*i}) = -(-1) = -e^{pi*i}> = -e^{2*pi*i/2}, and if f(e^{0*i})=-e^{0*i/2} then f(e^{2*pi*i})> = e^{2*pi*i/2}. This is where the wraparound comes in; if 0 is> in A then 2*pi is in B and vice-versa.> So in fact the original assumption that there was such an f was> false, Q.E.D.Can you switch to congruences? What about something like f(e^{it})^2 - e^{it} = 0(mod 35)in the ring of algebraic integers? > Now, a1 and a2 are not square roots, but they are similar enough> to a constant times the square root of m to make the same type of> argument apply.> Keith RamsayWhy don't you just give the a's explicitly and prove it then?James Harris === [...]|And you've gone off on a tangent. But as you mention it, I suggest|you go ahead and be *careful* instead of possibly hoping that you can|get away with casting doubt.||It's not a political discussion Keith Ramsay. You're not on Fox News.You're hardly in any position to complain, either about gliblyexpressing doubts about things you don't understand, or about makingpolitical statements, or about being careful either![...]| > If this is so, then one of the main questions is what values this| > common factor has when m is not 0. I don't see a problem with saying| > it's f when m=0, but I also don't see why it shouldn't be a varying| > factor of f as m changes.| | Yeah, and I gave an example yesterday which should tell you why.| | P(x) = 2x^2 + 4x + 2| | (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2| | a_1 a_2 = 2x^2,Is this last equation another assumption? Otherwise, what's to ruleout a_1=1, a_2 = x^2+2x-1, for instance? | and I note that when x=0, at *least* one of the a's must equal 0, and| further note that the constant term of the factor a_1 + 1, which I'll| call g_1 is 1 at that point. Further the factor a_2 + 2 has a factor| that is 2 at that point, and I'll call it g_2.|| Now then Keith Ramsay, do you question what g_2 will do when x does| not equal 0?| | So why do you do it above?Continually expressing shock that I don't agree with you, when youhaven't indicated a principle to justify your claim, is just a bunchof posturing. What's the general principle?| Ultimately, you may try and claim that irreducibility over Q is what's| pertinent, if so, explain in detail.The two cases aren't parallel. You really should get out of thehabit of thinking that analogy and cajolery add up to a logicalargument. Giving a bunch of examples which work the way you wantanother example to work is not a proof.If I were to give an explanation for why the examples that work,work, I'd give it in terms of the following principle: (*) If a divides bc, then there exist m and n such that a=mn, m divides b and n divides c.You give examples where the product of two polynomials is divisibleby an integer. Given that (*) is true in these cases, we can thentry to ?ure out what m and n would work by considering the constantterms and so on as you do. All of your simpli?d examples are oneswhere (*) works.But (*) is not generally true for functions having algebraic integervalues.[...]| > | >Or do you mean| > | > something else? Is it a fair paraphrase of the step where you| > | > introduce a1, a2, and a3, to say that they are three functions from| > | > the algebraic integers to the algebraic integers, a1(m), a2(m), and| > | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for| > | > every x?| > | | > | They're not necessarily functions of m.| > | > At some point you need actually to say what kind of thing a1, a2, and| > a3 are, without leaving any special wriggle room. If treating them as| > functions of m is not quite good enough, then you really need to say| > what they are.| | You didn't connect back with your own statement, fascinating.| | I'm repeating myself with that statement, but before you talked of| reparametrization in reply.| | I fear you are a parrot. You look for key words and then regurgitate| based on something you think is relevant, but you need to THINK.I didn't think I would need to put in the previous quoted text inorder for you to remember what you had just written:#> Perhaps it would help if you clari?d and/or con?med a few things.#> When in the paper you write that g1 must have that same factor (of#> f) in general, does in general mean that you're saying the value#> of g1 for each allowed value of m is divisible by f? ##It depends on context. It's like if you have y=2x+1, and consider#various values. Now I see pressure to write that as f(x)=2x+1, but I#don't think it's worth the potential confusion.##The problem is that though you see m as the key variable, it may in#fact be a *factor* of m that is the true independent variable, which#I'm sure has confused quite a few people. Now it's a measure of your#mathematical ability if you know what I mean there, and let's just say#that I'm not interested in expanding out in a way that leaves *more*#room for confusion.So you're telling us that m might not be the true independentvariable. Do you realize that switching from one independentvariable to another one is known as reparametrizing?A reasonable reader, who had read the paper but not this discussion,would naturally tend to suspect that a1, a2 and a3, which aredescribed as having values at given values of m, would tend tosuspect that they are simply functions of m. If this is notnecessarily so, it's because you've left out any explanation forwhat else you intend for them to be.This stuff about how being more speci? is bad because the rest ofus (being inferior to you in mathematical ability of course) wouldbe liable to be confused is just an excuse. You are, because ofyour lack of practice in writing actual proofs, failing to bespeci?, and as a result getting confused. I think you're just tryingto bluff your way past the fact that you don't know how to de?ethem in such a way as to get the argument in the paper to work.Keith Ramsay === [...]|And you've gone off on a tangent. But as you mention it, I suggest|you go ahead and be *careful* instead of possibly hoping that you can|get away with casting doubt.||It's not a political discussion Keith Ramsay. You're not on Fox News.You're hardly in any position to complain, either about gliblyexpressing doubts about things you don't understand, or about makingpolitical statements, or about being careful either![...]| > If this is so, then one of the main questions is what values this| > common factor has when m is not 0. I don't see a problem with saying| > it's f when m=0, but I also don't see why it shouldn't be a varying| > factor of f as m changes.| | Yeah, and I gave an example yesterday which should tell you why.| | P(x) = 2x^2 + 4x + 2| | (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2| | a_1 a_2 = 2x^2,Is this last equation another assumption? Otherwise, what's to ruleout a_1=1, a_2 = x^2+2x-1, for instance? | and I note that when x=0, at *least* one of the a's must equal 0, and| further note that the constant term of the factor a_1 + 1, which I'll| call g_1 is 1 at that point. Further the factor a_2 + 2 has a factor| that is 2 at that point, and I'll call it g_2.|| Now then Keith Ramsay, do you question what g_2 will do when x does| not equal 0?| | So why do you do it above?Continually expressing shock that I don't agree with you, when youhaven't indicated a principle to justify your claim, is just a bunchof posturing. What's the general principle?| Ultimately, you may try and claim that irreducibility over Q is what's| pertinent, if so, explain in detail.The two cases aren't parallel. You really should get out of thehabit of thinking that analogy and cajolery add up to a logicalargument. Giving a bunch of examples which work the way you wantanother example to work is not a proof.If I were to give an explanation for why the examples that work,work, I'd give it in terms of the following principle: (*) If a divides bc, then there exist m and n such that a=mn, m divides b and n divides c.You give examples where the product of two polynomials is divisibleby an integer. Given that (*) is true in these cases, we can thentry to ?ure out what m and n would work by considering the constantterms and so on as you do. All of your simpli?d examples are oneswhere (*) works.But (*) is not generally true for functions having algebraic integervalues.[...]| > | >Or do you mean| > | > something else? Is it a fair paraphrase of the step where you| > | > introduce a1, a2, and a3, to say that they are three functions from| > | > the algebraic integers to the algebraic integers, a1(m), a2(m), and| > | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for| > | > every x?| > | | > | They're not necessarily functions of m.| > | > At some point you need actually to say what kind of thing a1, a2, and| > a3 are, without leaving any special wriggle room. If treating them as| > functions of m is not quite good enough, then you really need to say| > what they are.| | You didn't connect back with your own statement, fascinating.| | I'm repeating myself with that statement, but before you talked of| reparametrization in reply.| | I fear you are a parrot. You look for key words and then regurgitate| based on something you think is relevant, but you need to THINK.I didn't think I would need to put in the previous quoted text inorder for you to remember what you had just written:#> Perhaps it would help if you clari?d and/or con?med a few things.#> When in the paper you write that g1 must have that same factor (of#> f) in general, does in general mean that you're saying the value#> of g1 for each allowed value of m is divisible by f? ##It depends on context. It's like if you have y=2x+1, and consider#various values. Now I see pressure to write that as f(x)=2x+1, but I#don't think it's worth the potential confusion.##The problem is that though you see m as the key variable, it may in#fact be a *factor* of m that is the true independent variable, which#I'm sure has confused quite a few people. Now it's a measure of your#mathematical ability if you know what I mean there, and let's just say#that I'm not interested in expanding out in a way that leaves *more*#room for confusion.So you're telling us that m might not be the true independentvariable. Do you realize that switching from one independentvariable to another one is known as reparametrizing?A reasonable reader, who had read the paper but not this discussion,would naturally tend to suspect that a1, a2 and a3, which aredescribed as having values at given values of m, would tend tosuspect that they are simply functions of m. If this is notnecessarily so, it's because you've left out any explanation forwhat else you intend for them to be.This stuff about how being more speci? is bad because the rest ofus (being inferior to you in mathematical ability of course) wouldbe liable to be confused is just an excuse. You are, because ofyour lack of practice in writing actual proofs, failing to bespeci?, and as a result getting confused. I think you're just tryingto bluff your way past the fact that you don't know how to de?ethem in such a way as to get the argument in the paper to work.Keith Ramsay === [...]|And you've gone off on a tangent. But as you mention it, I suggest|you go ahead and be *careful* instead of possibly hoping that you can|get away with casting doubt.||It's not a political discussion Keith Ramsay. You're not on Fox News.You're hardly in any position to complain, either about gliblyexpressing doubts about things you don't understand, or about makingpolitical statements, or about being careful either![...]| > If this is so, then one of the main questions is what values this| > common factor has when m is not 0. I don't see a problem with saying| > it's f when m=0, but I also don't see why it shouldn't be a varying| > factor of f as m changes.| | Yeah, and I gave an example yesterday which should tell you why.| | P(x) = 2x^2 + 4x + 2| | (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2| | a_1 a_2 = 2x^2,Is this last equation another assumption? Otherwise, what's to ruleout a_1=1, a_2 = x^2+2x-1, for instance? | and I note that when x=0, at *least* one of the a's must equal 0, and| further note that the constant term of the factor a_1 + 1, which I'll| call g_1 is 1 at that point. Further the factor a_2 + 2 has a factor| that is 2 at that point, and I'll call it g_2.|| Now then Keith Ramsay, do you question what g_2 will do when x does| not equal 0?| | So why do you do it above?Continually expressing shock that I don't agree with you, when youhaven't indicated a principle to justify your claim, is just a bunchof posturing. What's the general principle?| Ultimately, you may try and claim that irreducibility over Q is what's| pertinent, if so, explain in detail.The two cases aren't parallel. You really should get out of thehabit of thinking that analogy and cajolery add up to a logicalargument. Giving a bunch of examples which work the way you wantanother example to work is not a proof.If I were to give an explanation for why the examples that work,work, I'd give it in terms of the following principle: (*) If a divides bc, then there exist m and n such that a=mn, m divides b and n divides c.You give examples where the product of two polynomials is divisibleby an integer. Given that (*) is true in these cases, we can thentry to ?ure out what m and n would work by considering the constantterms and so on as you do. All of your simpli?d examples are oneswhere (*) works.But (*) is not generally true for functions having algebraic integervalues.[...]| > | >Or do you mean| > | > something else? Is it a fair paraphrase of the step where you| > | > introduce a1, a2, and a3, to say that they are three functions from| > | > the algebraic integers to the algebraic integers, a1(m), a2(m), and| > | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for| > | > every x?| > | | > | They're not necessarily functions of m.| > | > At some point you need actually to say what kind of thing a1, a2, and| > a3 are, without leaving any special wriggle room. If treating them as| > functions of m is not quite good enough, then you really need to say| > what they are.| | You didn't connect back with your own statement, fascinating.| | I'm repeating myself with that statement, but before you talked of| reparametrization in reply.| | I fear you are a parrot. You look for key words and then regurgitate| based on something you think is relevant, but you need to THINK.I didn't think I would need to put in the previous quoted text inorder for you to remember what you had just written:#> Perhaps it would help if you clari?d and/or con?med a few things.#> When in the paper you write that g1 must have that same factor (of#> f) in general, does in general mean that you're saying the value#> of g1 for each allowed value of m is divisible by f? ##It depends on context. It's like if you have y=2x+1, and consider#various values. Now I see pressure to write that as f(x)=2x+1, but I#don't think it's worth the potential confusion.##The problem is that though you see m as the key variable, it may in#fact be a *factor* of m that is the true independent variable, which#I'm sure has confused quite a few people. Now it's a measure of your#mathematical ability if you know what I mean there, and let's just say#that I'm not interested in expanding out in a way that leaves *more*#room for confusion.So you're telling us that m might not be the true independentvariable. Do you realize that switching from one independentvariable to another one is known as reparametrizing?A reasonable reader, who had read the paper but not this discussion,would naturally tend to suspect that a1, a2 and a3, which aredescribed as having values at given values of m, would tend tosuspect that they are simply functions of m. If this is notnecessarily so, it's because you've left out any explanation forwhat else you intend for them to be.This stuff about how being more speci? is bad because the rest ofus (being inferior to you in mathematical ability of course) wouldbe liable to be confused is just an excuse. You are, because ofyour lack of practice in writing actual proofs, failing to bespeci?, and as a result getting confused. I think you're just tryingto bluff your way past the fact that you don't know how to de?ethem in such a way as to get the argument in the paper to work.Keith Ramsay === [...]|And you've gone off on a tangent. But as you mention it, I suggest|you go ahead and be *careful* instead of possibly hoping that you can|get away with casting doubt.||It's not a political discussion Keith Ramsay. You're not on Fox News.You're hardly in any position to complain, either about gliblyexpressing doubts about things you don't understand, or about makingpolitical statements, or about being careful either![...]| > If this is so, then one of the main questions is what values this| > common factor has when m is not 0. I don't see a problem with saying| > it's f when m=0, but I also don't see why it shouldn't be a varying| > factor of f as m changes.| | Yeah, and I gave an example yesterday which should tell you why.| | P(x) = 2x^2 + 4x + 2| | (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2| | a_1 a_2 = 2x^2,Is this last equation another assumption? Otherwise, what's to ruleout a_1=1, a_2 = x^2+2x-1, for instance? | and I note that when x=0, at *least* one of the a's must equal 0, and| further note that the constant term of the factor a_1 + 1, which I'll| call g_1 is 1 at that point. Further the factor a_2 + 2 has a factor| that is 2 at that point, and I'll call it g_2.|| Now then Keith Ramsay, do you question what g_2 will do when x does| not equal 0?| | So why do you do it above?Continually expressing shock that I don't agree with you, when youhaven't indicated what principle it is that justi?s your claim,is just a bunch of posturing. What's the general principle?| Ultimately, you may try and claim that irreducibility over Q is what's| pertinent, if so, explain in detail.The two cases aren't parallel. You really should get out of thehabit of thinking that analogy and cajolery add up to a logicalargument. Giving a bunch of examples which work the way you wantanother example to work is not a proof.If I were to give an explanation for why the examples that work,work, I'd give it in terms of the following principle: (*) If a divides bc, then there exist m and n such that a=mn, m divides b and n divides c.You give examples where the product of two polynomials is divisibleby an integer. Given that (*) is true in these cases, we can thentry to ?ure out what m and n would work by considering the constantterms and so on as you do. All of your simpli?d examples are oneswhere (*) works.But (*) is not generally true for functions having algebraic integervalues.Another way to look at it is that in order to show that a1 is divisibleby f (say), you have either to show that all three of them are divisibleby f, or you have to make some additional assumption which somehow forces a1at each value of m not to be the value or one of the values of the three(a1, a2, and a3) that isn't divisible by f. If a1, a2 and a3 were simplythree functions of m, which at each speci? m satisfy the equation de?ingthem, then the order in which they're assigned to those three values is stillarbitrary, leaving nothing to keep a1 from being the wrong value.[...]| > | >Or do you mean| > | > something else? Is it a fair paraphrase of the step where you| > | > introduce a1, a2, and a3, to say that they are three functions from| > | > the algebraic integers to the algebraic integers, a1(m), a2(m), and| > | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for| > | > every x?| > | | > | They're not necessarily functions of m.| > | > At some point you need actually to say what kind of thing a1, a2, and| > a3 are, without leaving any special wriggle room. If treating them as| > functions of m is not quite good enough, then you really need to say| > what they are.| | You didn't connect back with your own statement, fascinating.| | I'm repeating myself with that statement, but before you talked of| reparametrization in reply.| | I fear you are a parrot. You look for key words and then regurgitate| based on something you think is relevant, but you need to THINK.I didn't think I would need to put in the previous quoted text inorder for you to remember what you had just written:|> Perhaps it would help if you clari?d and/or con?med a few things.|> When in the paper you write that g1 must have that same factor (of|> f) in general, does in general mean that you're saying the value|> of g1 for each allowed value of m is divisible by f? ||It depends on context. It's like if you have y=2x+1, and consider|various values. Now I see pressure to write that as f(x)=2x+1, but I|don't think it's worth the potential confusion.||The problem is that though you see m as the key variable, it may in|fact be a *factor* of m that is the true independent variable, which|I'm sure has confused quite a few people. Now it's a measure of your|mathematical ability if you know what I mean there, and let's just say|that I'm not interested in expanding out in a way that leaves *more*|room for confusion.So you're telling us that m might not be the true independentvariable. Do you realize that switching from one independentvariable to another one is known as reparametrizing?A reasonable person reading the proof (and not this discussion)would look at that formula supposedly de?ing a1, a2, and a3,and since you don't say speci?ally what they are, they'd have tomake a bit of a guess. That they are at least functions of m wouldbe quite a reasonable interpolation. Otherwise, you're leaving themin the dark.This stuff about how being more speci? is bad because the rest ofus (being inferior to you in mathematical ability of course) wouldbe liable to be confused is just an excuse. You are, because ofyour lack of practice in writing actual proofs, failing to bespeci?, and as a result getting confused.I think you're just trying to bluff your way past the problem. Anybodywho actually had a proof would be able to answer such simple questionsas these much more speci?ally.Keith Ramsay === > If my explanation isn't working, ?e, someone will eventually ?d> a better way of explaining it to you.> That is an irrational statement. Where do you suppose this someone> is?The someone who can bring JSH to understanding does not exist. === >> Remember (unlike e.g. the Gaussian integers) the algebraic integers>> are dense in the complex plane, meaning that any circle, no matter>> how small, has algebraic integers inside it.>>Hmmm...interesting assertion, but what about singularities?I'll bite. What about singularities?We aren't talking about a function here, just about two sets, thecomplex numbers and the algebraic integers. There aren't anysingularities. And if there were, what does that have to do withwhether there are in?itely many algebraic integers everywhere youlook? - Randy === Sorry about the duplicate postings; I got caught by this thing whereI get a connection timed out page while trying to post with Google,but apparently the posting goes out anyway.[...]| > Remember (unlike e.g. the Gaussian integers) the algebraic integers| > are dense in the complex plane, meaning that any circle, no matter| > how small, has algebraic integers inside it.| | Hmmm...interesting assertion, but what about singularities?As usual by a circle I mean one having positive radius, which doesn'thave singularities.[...]| > No, my main point in bringing this stuff up was to try to convince| > you that de?ing a1, a2, and a3 in such a way that their values at| > one point are related to their values at other points in a useful way.| | Um, but that is an insinuation that they aren't already rigorously| de?ed, when in fact they are.I don't see much sign of your knowing what it means to give a rigorousBut an equation is only meaningful if one knows somehow what kind ofthings the terms in it represent. The paper refers to the value onehas at m=0, so there has to be some sense in which one can substitutem=0 into one of them. It's natural then to assume you mean for themto be functions of m. But then you say that they're not necessarilyfunctions of m, without saying speci?ally what else they might be.(You hint that expanding on this point might cause confusion.)Obviously you're not giving a rigorous de?ition.| > If my explanation isn't working, ?e, someone will eventually ?d| > a better way of explaining it to you.| | That is an irrational statement. Where do you suppose this someone| is?I see at least a couple of other people who also understand this pointabout how the values of a1, a2, and a3 at one point relate to theirvalues at another point, and have been trying to explain it to you.I'm just assuming that eventually one of us will come up with a betterway of explaining it to you.| Possibly your memory tells you they're in some potential ?ld??? [...]| That is false as the a's are determined both in form and type.As in, sort of like functions of m but not necessarily, and youwouldn't want to confuse poor confused us by going into furtherdetails about it.| > Second, p-adic numbers ARE exact. They're just a different system.| > It's easier in a lot of ways to be rigorous with them than it is| > to be rigorous with the real numbers or the complex numbers.| | Is that something you have from memory Keith Ramsay?No, from my own experience.| > Third, you're surely aware that nobody will be ripping anybody| > apart or forcing anybody to do anything. People have tried hard| > to force you down to rigor, for example by telling you what,| > allegedly, the common factors between 5 and the roots of that cubic| > are. Doesn't phase you a bit! And you've shown us all how easy it is| > to be impervious to demands for rigor.| | That's an appeal to the gallery, which is a logical fallacy.I'm just answering this suggestion you made that if I had a furtherexplanation in mind using p-adic numbers, you were going to rip meapart and force me to be rigorous. I'll be less likely to remind youof how poor your rigor has been up until now, if you refrain frombold predictions about what mine is going to be like in the future.[...]| > So in fact the original assumption that there was such an f was| > false, Q.E.D.| | Can you switch to congruences? What about something like | | f(e^{it})^2 - e^{it} = 0(mod 35)| | in the ring of algebraic integers?That's an interesting question. The multiples of 35 in the algebraicintegers are also dense, which means that we have a lot of freedomto adjust the values of f. I would guess that this makes it possibleto have a function f which is continuous on the whole complex planeand satis?s f(z)^2 = z (mod 35) for all algebraic integers z, butI would have to think some more to prove it.e^{it} is an algebraic integer only for certain selected t, of course. | > Now, a1 and a2 are not square roots, but they are similar enough| > to a constant times the square root of m to make the same type of| > argument apply.| > | > Keith Ramsay| | Why don't you just give the a's explicitly and prove it then?If you mean the a1, a2 and a3 as I would de?e them, i.e. asfunctions on the complex integers with complex integer values,it's just the time required. Applying the cubic formula, as youseem to be suggesting I do, is pretty tedious when the coef?ientsare expressions involving m and another constant or two. We'll seewhether I have enough spare time this week.If it's a1, a2 and a3 that might have a different independentvariable than m, it would of course depend upon what that variableis.Keith Ramsay === [...]>>Remember (unlike e.g. the Gaussian integers) the algebraic integers>>are dense in the complex plane, meaning that any circle, no matter>>how small, has algebraic integers inside it.> Hmmm...interesting assertion, but what about singularities?[...] 2> sqrt(2) > 1 so, 1> sqrt(2) - 1 >0Also, sqrt(2) - 1 is an algebraic integer because sqrt(2) and 1 are.In fact, 1/2 > sqrt(2) - 1 >0 .So for any n>=1: (1/2)^n > (sqrt(2) - 1)^n > 0 .Note that, by repeated multiplication, (sqrt(2) - 1)^n is also analgebraic integer.Given any positive real number d, there exists an n such that: d> (sqrt(2) - 1)^n > 0.Letting M and N vary through all ordinary integers, we get a latticeor square grid from the collection of algebraic integers M* (sqrt(2)-1)^n + N*i*(sqrt(2)-1)^n .The basic , small squares in the grid have a side of (sqrt(2) - 1)^n < d [ the n depends on d...]So we can construct grids with d=0.1, 0.01, 0.001, .... d= 10^(-100) ... , and all the numbers in all the gridsare algebraic integers.David Bernier === >> Remember (unlike e.g. the Gaussian integers) the algebraic integers>> are dense in the complex plane, meaning that any circle, no matter>> how small, has algebraic integers inside it.>> >Hmmm...interesting assertion, but what about singularities?> > I'll bite. What about singularities?> We aren't talking about a function here, just about two sets, the> complex numbers and the algebraic integers. There aren't any> singularities. And if there were, what does that have to do with> whether there are in?itely many algebraic integers everywhere you> look?> - RandyA singularity is a circle of 0 radius, and in the complex plane I canpick an in?ite number of fractions.Fascinating how far the discussion is from my paper, but maybe not sofar from the subject line, eh?James Harris === > [...]> |And you've gone off on a tangent. But as you mention it, I suggest> |you go ahead and be *careful* instead of possibly hoping that you can> |get away with casting doubt.> |> |It's not a political discussion Keith Ramsay. You're not on Fox News.> You're hardly in any position to complain, either about glibly> expressing doubts about things you don't understand, or about making> political statements, or about being careful either!Support what you say mathematically. It's not a political discussionand you're not on Fox News!> [...]> | > If this is so, then one of the main questions is what values this> | > common factor has when m is not 0. I don't see a problem with saying> | > it's f when m=0, but I also don't see why it shouldn't be a varying> | > factor of f as m changes.> | > | Yeah, and I gave an example yesterday which should tell you why.> | > | P(x) = 2x^2 + 4x + 2> | > | (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2> | > | a_1 a_2 = 2x^2,> Is this last equation another assumption? Otherwise, what's to rule> out a_1=1, a_2 = x^2+2x-1, for instance?The last equation rules it out, which is why I gave it.> | and I note that when x=0, at *least* one of the a's must equal 0, and> | further note that the constant term of the factor a_1 + 1, which I'll> | call g_1 is 1 at that point. Further the factor a_2 + 2 has a factor> | that is 2 at that point, and I'll call it g_2.> |> | Now then Keith Ramsay, do you question what g_2 will do when x does> | not equal 0?> | > | So why do you do it above?> Continually expressing shock that I don't agree with you, when you> haven't indicated a principle to justify your claim, is just a bunch> of posturing. What's the general principle?The general principle is that factors of polynomials can be written asr+c, where r varies or is 0, while c is constant.That's it. Like I've said before that simple thing is the linchpin ofmy position.To refute my mathematical argument, you have to refute it.However, posters keep making long-winded posts that manage to avoidit.> | Ultimately, you may try and claim that irreducibility over Q is what's> | pertinent, if so, explain in detail.> The two cases aren't parallel. You really should get out of the> habit of thinking that analogy and cajolery add up to a logical> argument. Giving a bunch of examples which work the way you want> another example to work is not a proof.I've given the proof. > If I were to give an explanation for why the examples that work,> work, I'd give it in terms of the following principle:> (*) If a divides bc, then there exist m and n such that a=mn,> m divides b and n divides c.> You give examples where the product of two polynomials is divisible> by an integer. Given that (*) is true in these cases, we can then> try to ?ure out what m and n would work by considering the constant> terms and so on as you do. All of your simpli?d examples are ones> where (*) works.>> But (*) is not generally true for functions having algebraic integer> values.Irrelevant.> [...]> | > | >Or do you mean> | > | > something else? Is it a fair paraphrase of the step where you> | > | > introduce a1, a2, and a3, to say that they are three functions from> | > | > the algebraic integers to the algebraic integers, a1(m), a2(m), and> | > | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for> | > | > every x?> | > | > | > | They're not necessarily functions of m.> | > | > At some point you need actually to say what kind of thing a1, a2, and> | > a3 are, without leaving any special wriggle room. If treating them as> | > functions of m is not quite good enough, then you really need to say> | > what they are.> | > | You didn't connect back with your own statement, fascinating.> | > | I'm repeating myself with that statement, but before you talked of> | reparametrization in reply.> | > | I fear you are a parrot. You look for key words and then regurgitate> | based on something you think is relevant, but you need to THINK.> I didn't think I would need to put in the previous quoted text in> order for you to remember what you had just written:It's not necessary that they be functions of m. The question ofwhether or not the a's for the speci? example I gave are functionsof m, keeps coming up, but it's not really relevant.In general, there is no necessity that given P(x), a factor of P(x)can be written as a function of x plus a constant.> #> Perhaps it would help if you clari?d and/or con?med a few things.> #> When in the paper you write that g1 must have that same factor (of> #> f) in general, does in general mean that you're saying the value> #> of g1 for each allowed value of m is divisible by f? > #> #It depends on context. It's like if you have y=2x+1, and consider> #various values. Now I see pressure to write that as f(x)=2x+1, but I> #don't think it's worth the potential confusion.> #> #The problem is that though you see m as the key variable, it may in> #fact be a *factor* of m that is the true independent variable, which> #I'm sure has confused quite a few people. Now it's a measure of your> #mathematical ability if you know what I mean there, and let's just say> #that I'm not interested in expanding out in a way that leaves *more*> #room for confusion.> So you're telling us that m might not be the true independent> variable. Do you realize that switching from one independent> variable to another one is known as reparametrizing?That's not relevant.> A reasonable reader, who had read the paper but not this discussion,> would naturally tend to suspect that a1, a2 and a3, which are> described as having values at given values of m, would tend to> suspect that they are simply functions of m. If this is not> necessarily so, it's because you've left out any explanation for> what else you intend for them to be.Questions about whether or not they're functions of m are notrelevant.> This stuff about how being more speci? is bad because the rest of> us (being inferior to you in mathematical ability of course) would> be liable to be confused is just an excuse. You are, because of> your lack of practice in writing actual proofs, failing to be> speci?, and as a result getting confused. I think you're just trying> to bluff your way past the fact that you don't know how to de?e> them in such a way as to get the argument in the paper to work.The paper has a lemma. Given that lemma its conclusion follows easilyenough.If you have a problem with the paper, you need to show itmathematically, instead of talking on all these extraneous subjects.For instance, the question of whether or not the a's are functions ofm, is irrelevant. The lemma is in the paper for a reason. In dodgingthe lemma and in continually bringing up irrelevant issues, it seemsto me that you are deliberately being intellectually dishonest, with aperverse need to try and in? others to believe falsehoods.James Harris === [snip]> The paper has a lemma. Given that lemma its conclusion follows easily> enough.The lemma is wrong.> If you have a problem with the paper, you need to show it> mathematically, instead of talking on all these extraneous subjects.The errors have been shown mathematically already. You have chosen to ignore the truth.> For instance, the question of whether or not the a's are functions of> m, is irrelevant. The lemma is in the paper for a reason. In dodging> the lemma and in continually bringing up irrelevant issues, it seems> to me that you are deliberately being intellectually dishonest, with a> perverse need to try and in? others to believe falsehoods.The arguments you present in your paper have been conclusively refuted. It is you who are beingintellectually dishonest, with a perverse need to try and in? others to believe falsehoods.You have consistently revealed yourself to be a defender of lies and an enemy of truth. When confronted withspeci? errors you ignore the facts and continue your delirium.James Harris, you should be ashamed of your behavior -- especially since you persist in document it in publicrecords.--A man with integrity will identify, acknowledge and correct his errors. A man without integrity will ignore,deny or defend them.--Democracy: The triumph of popularity over principle.--http://www.crbond.com === > Sorry about the duplicate postings; I got caught by this thing where> I get a connection timed out page while trying to post with Google,> but apparently the posting goes out anyway.> [...]> | > Remember (unlike e.g. the Gaussian integers) the algebraic integers> | > are dense in the complex plane, meaning that any circle, no matter> | > how small, has algebraic integers inside it.> | > | Hmmm...interesting assertion, but what about singularities?> > As usual by a circle I mean one having positive radius, which doesn't> have singularities.0 is a positive number. > [...]> | > No, my main point in bringing this stuff up was to try to convince> | > you that de?ing a1, a2, and a3 in such a way that their values at> | > one point are related to their values at other points in a useful way.> | > | Um, but that is an insinuation that they aren't already rigorously> | de?ed, when in fact they are.> I don't see much sign of your knowing what it means to give a rigorous> But an equation is only meaningful if one knows somehow what kind of> things the terms in it represent. The paper refers to the value one> has at m=0, so there has to be some sense in which one can substitute> m=0 into one of them. It's natural then to assume you mean for them> to be functions of m. But then you say that they're not necessarily> functions of m, without saying speci?ally what else they might be.> (You hint that expanding on this point might cause confusion.)> Obviously you're not giving a rigorous de?ition.Obviously?The a's are de?ed by (v^3+1)x^3 -3vxy^2 + y^3 = (a_1 x + y)(a_2 x + y)(a_3 x + y),where v=-1+mf^2.claims with mathematics. > | > If my explanation isn't working, ?e, someone will eventually ?d> | > a better way of explaining it to you.> | > | That is an irrational statement. Where do you suppose this someone> | is?> I see at least a couple of other people who also understand this point> about how the values of a1, a2, and a3 at one point relate to their> values at another point, and have been trying to explain it to you.> I'm just assuming that eventually one of us will come up with a better> way of explaining it to you.Well I should have helped you and these hypothetical others out withthe information above. Solve that cubic and see what happens.> | Possibly your memory tells you they're in some potential ?ld?> ??Don't worry about it.> [...]> | That is false as the a's are determined both in form and type.> As in, sort of like functions of m but not necessarily, and you> wouldn't want to confuse poor confused us by going into further> details about it.The a's are de?ed by (v^3+1)x^3 -3vxy^2 + y^3 = (a_1 x + y)(a_2 x + y)(a_3 x + y),where v=-1+mf^2.And how do you know? Wouldn't it be from your *memory* Keith Ramsay?That's why it's called experience, as in it happened in the past, soyou have to use memory unless possibly you're relying on writings? > | > Third, you're surely aware that nobody will be ripping anybody> | > apart or forcing anybody to do anything. People have tried hard> | > to force you down to rigor, for example by telling you what,> | > allegedly, the common factors between 5 and the roots of that cubic> | > are. Doesn't phase you a bit! And you've shown us all how easy it is> | > to be impervious to demands for rigor.> | > | That's an appeal to the gallery, which is a logical fallacy.> I'm just answering this suggestion you made that if I had a further> explanation in mind using p-adic numbers, you were going to rip me> apart and force me to be rigorous. I'll be less likely to remind you> of how poor your rigor has been up until now, if you refrain from> bold predictions about what mine is going to be like in the future.Your mathematical arguments should stand on their own Keith Ramsay. And there's no need to shrink back if you're correct. It's about themath, not your fears. > [...]> | > So in fact the original assumption that there was such an f was> | > false, Q.E.D.> | > | Can you switch to congruences? What about something like > | > | f(e^{it})^2 - e^{it} = 0(mod 35)> | > | in the ring of algebraic integers?> That's an interesting question. The multiples of 35 in the algebraic> integers are also dense, which means that we have a lot of freedom> to adjust the values of f. I would guess that this makes it possible> to have a function f which is continuous on the whole complex plane> and satis?s f(z)^2 = z (mod 35) for all algebraic integers z, but> I would have to think some more to prove it.> e^{it} is an algebraic integer only for certain selected t, of course. Of course. Feel free to think further on it.> | > Now, a1 and a2 are not square roots, but they are similar enough> | > to a constant times the square root of m to make the same type of> | > argument apply.> | > > | > Keith Ramsay> | > | Why don't you just give the a's explicitly and prove it then?> If you mean the a1, a2 and a3 as I would de?e them, i.e. as> functions on the complex integers with complex integer values,> it's just the time required. Applying the cubic formula, as you> seem to be suggesting I do, is pretty tedious when the coef?ients> are expressions involving m and another constant or two. We'll see> whether I have enough spare time this week.> If it's a1, a2 and a3 that might have a different independent> variable than m, it would of course depend upon what that variable> is.> Keith RamsaySo you're admitting to bringing up what I've called irrelevant issueswithout having actually checked them, while refusing to fullyacknowledge the mathematical argument in the paper including a ratherbasic lemma that you simply don't mention.James Harris === ... stuff deleted ...> The paper has a lemma. Given that lemma its conclusion follows easily> enough.> If you have a problem with the paper, you need to show it> mathematically, instead of talking on all these extraneous subjects.> I have shown that your Primary Argument reaches a false conclusion,by showing (what I'm sure you must have seen by now, but are choosingto ignore) explicit formulas for factors that each of your a's havein common with 5.Surely that cannot be considered extraneous, as it has to do withwhat one must assume is the primary result in the paper. Thatprimary result is false, thus your argument must be incorrect.in threads that you have started, and keep participating in. Thearithmetic is simple, if tedious, and the argument, unlike yours,can be veri?d, line by line.Yet, you persist in this denial.the argument. Just say the word.> For instance, the question of whether or not the a's are functions of> m, is irrelevant. The lemma is in the paper for a reason. In dodging> the lemma and in continually bringing up irrelevant issues, it seems> to me that you are deliberately being intellectually dishonest, with a> perverse need to try and in? others to believe falsehoods.> Is it irrelevant to point out that your conclusion (regarding the a'sbeing coprime to 5) is false? Do you deny that I have done this?Is it perverse to have demonstrated the falsity of your conclusion?Is it perverse to mention that fact?Is it a falsehood that I am perpetrating?If so, then why?If not, then why do you insist on asserting that othersare lying, when you knowingly insist that an incorrectresult is true?> James HarrisDale. === >>[...]>>| > If this is so, then one of the main questions is what values this>>| > common factor has when m is not 0. I don't see a problem with saying>>| > it's f when m=0, but I also don't see why it shouldn't be a varying>>| > factor of f as m changes.>>| >>| Yeah, and I gave an example yesterday which should tell you why.>>| >>| P(x) = 2x^2 + 4x + 2>>| >>| (a_1 + 1)(a_2 + 2) = 2x^2 + 4x + 2>>| >>| a_1 a_2 = 2x^2,>>Is this last equation another assumption? Otherwise, what's to rule>>out a_1=1, a_2 = x^2+2x-1, for instance?> The last equation rules it out, which is why I gave it.The last equation is not necessarily true. What must be true is that a_1(x) a_2(x) + a_2(x) + 2 a_1(x) = 2x^2 + 4x. Because we do not know the a_i(x) are polynomials, we cannot assume that they will behave exactly the way terms of a polynomial would.>>| and I note that when x=0, at *least* one of the a's must equal 0, and>>| further note that the constant term of the factor a_1 + 1, which I'll>>| call g_1 is 1 at that point. Further the factor a_2 + 2 has a factor>>| that is 2 at that point, and I'll call it g_2.>>|>>| Now then Keith Ramsay, do you question what g_2 will do when x does>>| not equal 0?>>| >>| So why do you do it above?>>Continually expressing shock that I don't agree with you, when you>>haven't indicated a principle to justify your claim, is just a bunch>>of posturing. What's the general principle?> The general principle is that factors of polynomials can be written as> r+c, where r varies or is 0, while c is constant.This is trivially true, but because you have failed to say anything further about the nature of r, it also communicates virtually nothing.> That's it. Like I've said before that simple thing is the linchpin of> my position.It's trivially true, but you've done nothing rigorous with it.> To refute my mathematical argument, you have to refute it.No one is trying to refute that fact. It's the conclusions you leap to from it that are the problem. If you say something a little more precise about r, then you may be able to ?l in the holes in your lemma.> However, posters keep making long-winded posts that manage to avoid> it.No, it's the only part of the paper that is true. It's the *rest* of your paper that has problems.>>| Ultimately, you may try and claim that irreducibility over Q is what's>>| pertinent, if so, explain in detail.>>The two cases aren't parallel. You really should get out of the>>habit of thinking that analogy and cajolery add up to a logical>>argument. Giving a bunch of examples which work the way you want>>another example to work is not a proof.> I've given the proof.No, you've given a claim that you have failed to defend. You also tend to change the subject or start new threads rather than deal with the problems that have been shown.>>If I were to give an explanation for why the examples that work,>>work, I'd give it in terms of the following principle:>> (*) If a divides bc, then there exist m and n such that a=mn,>> m divides b and n divides c.>>You give examples where the product of two polynomials is divisible>>by an integer. Given that (*) is true in these cases, we can then>>try to ?ure out what m and n would work by considering the constant>>terms and so on as you do. All of your simpli?d examples are ones>>where (*) works.>>But (*) is not generally true for functions having algebraic integer>>values.> Irrelevant.> What you are trying to prove, and the reason your proof doesn't work is irrelevant? How does that work?>>[...]>>| > | >Or do you mean>>| > | > something else? Is it a fair paraphrase of the step where you>>| > | > introduce a1, a2, and a3, to say that they are three functions from>>| > | > the algebraic integers to the algebraic integers, a1(m), a2(m), and>>| > | > a3(m), having the property that P(m) = (a1*x+uf)(a2*x+uf)(a3*x+uf) for>>| > | > every x?>>| > | >>| > | They're not necessarily functions of m.>>| >>| > At some point you need actually to say what kind of thing a1, a2, and>>| > a3 are, without leaving any special wriggle room. If treating them as>>| > functions of m is not quite good enough, then you really need to say>>| > what they are.>>| >>| You didn't connect back with your own statement, fascinating.>>| >>| I'm repeating myself with that statement, but before you talked of>>| reparametrization in reply.>>| >>| I fear you are a parrot. You look for key words and then regurgitate>>| based on something you think is relevant, but you need to THINK.>>I didn't think I would need to put in the previous quoted text in>>order for you to remember what you had just written:> It's not necessary that they be functions of m. The question of> whether or not the a's for the speci? example I gave are functions> of m, keeps coming up, but it's not really relevant.> In general, there is no necessity that given P(x), a factor of P(x)> can be written as a function of x plus a constant.They can be constant functions of x. Then you have a constant (written as a function) plus a constant. Also note that you've just said it's ok to do what you objected to at the beginning of this post. Keith made a_1(x) = 1, a_2(x)=x^2+2x-1. Here, a_1(x)+1 is in the form constant + constant. Is this ok or not?>>#> Perhaps it would help if you clari?d and/or con?med a few things.>>#> When in the paper you write that g1 must have that same factor (of>>#> f) in general, does in general mean that you're saying the value>>#> of g1 for each allowed value of m is divisible by f? >>#>>#It depends on context. It's like if you have y=2x+1, and consider>>#various values. Now I see pressure to write that as f(x)=2x+1, but I>>#don't think it's worth the potential confusion.>>#>>#The problem is that though you see m as the key variable, it may in>>#fact be a *factor* of m that is the true independent variable, which>>#I'm sure has confused quite a few people. Now it's a measure of your>>#mathematical ability if you know what I mean there, and let's just say>>#that I'm not interested in expanding out in a way that leaves *more*>>#room for confusion.>>So you're telling us that m might not be the true independent>>variable. Do you realize that switching from one independent>>variable to another one is known as reparametrizing?> That's not relevant.Are you saying it doesn't matter what your independent variables are? If so, then you aren't saying anything and can draw no conclusions. It may be inconvenient, but is highly relevant.>>A reasonable reader, who had read the paper but not this discussion,>>would naturally tend to suspect that a1, a2 and a3, which are>>described as having values at given values of m, would tend to>>suspect that they are simply functions of m. If this is not>>necessarily so, it's because you've left out any explanation for>>what else you intend for them to be.> Questions about whether or not they're functions of m are not> relevant.If they cannot vary with m, they are constants. If they are constants, they can be computed and we can easily verify whether your paper is true. If they do vary with m, they are functions of m. In that case, different types of analysis can be done on them. If we don't know what is being talked about, then there is no way to conclude anything. You are refusing to address the key issue of de?ing what you are talking about. When you do that, you are not saying anything meaningful. Instead, you are babbling.>>This stuff about how being more speci? is bad because the rest of>>us (being inferior to you in mathematical ability of course) would>>be liable to be confused is just an excuse. You are, because of>>your lack of practice in writing actual proofs, failing to be>>speci?, and as a result getting confused. I think you're just trying>>to bluff your way past the fact that you don't know how to de?e>>them in such a way as to get the argument in the paper to work.> The paper has a lemma. Given that lemma its conclusion follows easily> enough.Then start by defending your lemma. There have been several objections (and disproofs) that you have completely failed to address.> If you have a problem with the paper, you need to show it> mathematically, instead of talking on all these extraneous subjects.> What do you think everyone's been doing? You are the one who brings up Fox News. You are the one who brings up politics. You are the one who brings up moral character and the supposed ?n our characters. Please deal with the math as we have been.> For instance, the question of whether or not the a's are functions of> m, is irrelevant. The lemma is in the paper for a reason. In dodging> the lemma and in continually bringing up irrelevant issues, it seems> to me that you are deliberately being intellectually dishonest, with a> perverse need to try and in? others to believe falsehoods.> The lemma has been shown to be highly questionable at best. You have failed to defend it. Who is dodging issues about the lemma?> James Harris-- Will Twentyman === > 0 is a positive number.What is your de?ition of a positive number?Can a number be both positive and negative?If you have a non-standard notion of positive,then the following argument may prove zero alsois negative.Suppose +x = -x.Then 2x = 0and x = 0.So, -0 = 0 = +0. === >> Sorry about the duplicate postings; I got caught by this thing where>> I get a connection timed out page while trying to post with Google,>> but apparently the posting goes out anyway.> [...]>> | > Remember (unlike e.g. the Gaussian integers) the algebraic integers>> | > are dense in the complex plane, meaning that any circle, no matter>> | > how small, has algebraic integers inside it.>> | >> | Hmmm...interesting assertion, but what about singularities?>> >> As usual by a circle I mean one having positive radius, which doesn't>> have singularities.>>0 is a positive number.Good one; about equivalent to your infamous integers areirrationals.No, 0 is NOT a positive number. Positive numbers are strictly largerthan 0. 0 is a non-negative number, and a non-positive number; it isnot a positive number. === ====================================== === =========Why do you take so much trouble to expose such a reasoner as Mr. Smith? I answer as a deceased friend of mine used to answer on like occasions - A man's capacity is no measure of his power to do mischief. Mr. Smith has untiring energy, which does something; self-evident honesty of conviction, which does more; and a long purse, which does most of all. He has made at least ten publications, full of ?ures few readers can critize. A great many people are staggered to this extend, that they imagine there must be the inde?ite something in the mysterious all this. They are brought to the point of suspicion that the mathematicians ought not to treat all this with such undisguised contempt, at least. -- A Budget of Paradoxes, Vol. 2 p. 129 by Augustus de Morgan === ======================================= === =========Arturo Magidinmagidin@math.berkeley.edu === [snip]Give it up, James Harris. Your so-called proof of FLT has gone down in ? Your pitiful attempts torescue it with diversions and side shows is laughable. You have covered the territory from gad?troll toloon to failure to fool to clown. Take down your idiotic and failed attempt at a proof. It's polluting theinternet.Recently you seem focussed on the notion that mathematicians are liars. (See topic of this thread.) Why notpost a list of those lies so others can observe them?--or are *you* the liar?--There are two things you must never attempt to prove: the unprovable -- and the obvious.--Democracy: The triumph of popularity over principle.--http://www.crbond.com === > 0 is a positive number.> What is your de?ition of a positive number?> Can a number be both positive and negative?> If you have a non-standard notion of positive,> then the following argument may prove zero also> is negative.> Suppose +x = -x.> Then 2x = 0> and x = 0.> So, -0 = 0 = +0.Oh, ok, if you all agree that 0 isn't a positive number that's ?e with me.James Harris === [snip....>> As usual by a circle I mean one having positive radius, which doesn't>> have singularities.>>0 is a positive number.> I think I have boiled all of JHs problems down.....[snip... === > 0 is a positive number. > What is your de?ition of a positive number?James must be a follower of Bourbaki.-- dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, +31205924131home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/ === > 0 is a positive number.> > What is your de?ition of a positive number?> Can a number be both positive and negative?> If you have a non-standard notion of positive,> then the following argument may prove zero also> is negative.> Suppose +x = -x.> Then 2x = 0> and x = 0.> So, -0 = 0 = +0.> Oh, ok, if you all agree that 0 isn't a positive number that's ?e with me.> James HarrisJust to keep JSH guessing, to the Bourbaki set, 0 is both positive and negative, but not strictly either. === [...]| > Obviously you're not giving a rigorous de?ition.| | Obviously?Yes.| The a's are de?ed by| | (v^3+1)x^3 -3vxy^2 + y^3 = (a_1 x + y)(a_2 x + y)(a_3 x + y),| | where v=-1+mf^2.You seem often to have the attitude that equations speak forthemselves. But if you had just left this equation by itself,it could have been referring to quaternion-valued functionsa_1(m), a_2(m) and a_3(m). Just writing an equation doesn't tellus what the equation means.But then you denied that guess. m is not necessarily the independentvariable. So evidently not only does the de?ition not quite saywhat type of functions or values the a_i are, it misleads the readerinto thinking that they're something more obvious than they are.Don't try to just skim past this issue of what the independentvariable is in these functions. | | a^3 + 3va^2 -(v^3+1) = 0, where again v=-1+mf^2, and the a's are its| roots.| | So you can solve for the a's and get some result, instead of endlessly| talking.The usual solution of the cubic starts by changing the variable toget rid of the square term. So let b = a+v, and we getb^3 - 3v^2b + (v^3-1) = 0. The discriminant is D = (v^3-1)^2/4 - v^6 = -(3/4)v^6 - (1/2)v^3 + (1/4) = -(3v^3 - 1)(v^3 + 1)/4.(although in number theory we use a different constant factor).This shows there are six values of v for which two of the rootscoincide.By Cardan's formula: b = ((1-v^3)/2 + sqrt(D))^{1/3} + ((1-v^3)/2 - sqrt(D))^{1/3},or a = ((1-v^3)/2 + sqrt(D))^{1/3} + ((1-v^3)/2 - sqrt(D))^{1/3} - v,| It might be especially interesting to see the result and see what| happens at v=-1.Because D = (v+1)(1-3v^3)(1+v+v^2)/4, near v=-1, D is approximatelyv+1. The two values of sqrt(D) trade places with each other as wesqrt(D) with -sqrt(D) wouldn't change the value of a. But the twocube roots are chosen so that at v=-1, for example, they are eitherboth 1, or one is (-1+sqrt(3)*i)/2 and the other is (-1-sqrt(3)*i)/2,or the ?st is (-1-sqrt(3)*i)/2 and the other is (-1+sqrt(3)*i)/2.So changing the sign on the square root of D is equivalent to leavingthe ?st root (where both cube roots are taken to be 1) alone, whileexchanging the other two roots. As I said before, if you take a looparound v=-1, the value of one of the roots comes back to the value ofthe other one. | Reminder to readers, Keith Ramsay has brought up a continuity| question, which actually is irrelevant, but what the hell?I was trying to convince you that it's unsafe to assume that thevalues of a_1, a_2, and a_3 extrapolate in a natural way from onevalue of m to another. This would be needed, for example, for a_2to be always divisible by f or anything like that. Otherwise, howcould it possibly be true that it's one particular one of the threethat has a certain divisibility property, if the manner in whichwe've decided which of the three roots to assign to each of thethree variables in an arbitrary way depending on the value of m?I'm sorry if the relevance doesn't seem clear to you.The one obvious way to attempt to extrapolate values of a_1, a_2and a_3 from one value of m to another is by continuity. Given apath in the complex plane which avoids all the points where twoof the roots coincide, we can see what happens to the a_i if wecontinuously change m along that path, while letting the a_i alsochange continuously as we go. Unfortunately (or fortunately,actually) which a_i is which when we reach the end of the pathwill depend upon which path we took from one endpoint to the other.So if I have a given value of a at m=0 (say a=0), the question ofwhich of the three values at m=1 corresponds to it is meaninglessunless I make an arbitrary convention.That's essentially what prevents them from being continuouseverywhere.I don't have the time today, but what one can do is to show thatfor each epsilon>0, there exists a delta>0 having the property thatif |v+1| < delta, then one of the roots is within epsilon of thenonzero root at v=-1 (what was it, a=1?), while the other two satisfy|a^2/(v+1) - C| < epsilon where C is some constant (probably just 1).Then we can consider the values v = -1+e^{it}. For small epsilon,the inequality forces a/e^{it/2} to be close to one of the squareroots of C. Then we can carry out the same argument as last timebut with the two sets being the t for which |a/e^{it/2} - sqrt(C)|is smaller and the t for which |a/e^{it/2} + sqrt(C)| is smaller.[...]| So you're admitting to bringing up what I've called irrelevant issues| without having actually checked them, while refusing to fully| acknowledge the mathematical argument in the paper including a rather| basic lemma that you simply don't mention.I ?d the lemma very uninteresting. I don't understand how youmanage to think of it as important.Similar to a lot of arguments written by undergraduate math majorsearly in their studies, this argument plods its way slowly throughthe routine parts of the argument, but condenses into a rapid sprintthe part which is most in need of explanation, and also hardest tobelieve.Keith Ramsay === > [...]> | > Obviously you're not giving a rigorous de?ition.> | > | Obviously?> Yes.Let's see if you support your accusation.> | The a's are de?ed by> | > | (v^3+1)x^3 -3vxy^2 + y^3 = (a_1 x + y)(a_2 x + y)(a_3 x + y),> | > | where v=-1+mf^2.> You seem often to have the attitude that equations speak for> themselves. But if you had just left this equation by itself,> it could have been referring to quaternion-valued functions> a_1(m), a_2(m) and a_3(m). Just writing an equation doesn't tell> us what the equation means.On the contrary, the equation clearly shows that there is afactorization.> a_1, a_2, and a_3 to be functions de?ed for algebraic integers m,> with algebraic integer values, having the property that for each m> they make the equation above hold for all x and y.Of course the ring is algebraic integers as that's been the ringthroughout the thread and is the ring in the paper Advanced PolynomialFactorization.The factorization should hold for all f, m, x and y, in the ring.There is no need to mention functions. > If that guess had been correct, then I would have said that the> de?ition was at least close to rigorous, just leaving a couple of> things implicit that should be explicit. All that it would take to> make it rigorous would be a few clarifying words. (As I tried to> explain to you before, you also couldn't be taking x to be a constant,> for example.)That's false. There is no requirement on the factorization that x notbe constant.Factorizations don't work that way.> But then you denied that guess. m is not necessarily the independent> variable. So evidently not only does the de?ition not quite say> what type of functions or values the a_i are, it misleads the reader> into thinking that they're something more obvious than they are.Factorizations are not dependent on the dependency of the variables.> Don't try to just skim past this issue of what the independent> variable is in these functions.Factorizations are not dependent on functions.> | > | a^3 + 3va^2 -(v^3+1) = 0, where again v=-1+mf^2, and the a's are its> | roots.> | > | So you can solve for the a's and get some result, instead of endlessly> | talking.> The usual solution of the cubic starts by changing the variable to> get rid of the square term. So let b = a+v, and we get> b^3 - 3v^2b + (v^3-1) = 0. The discriminant is> D = (v^3-1)^2/4 - v^6> = -(3/4)v^6 - (1/2)v^3 + (1/4)> = -(3v^3 - 1)(v^3 + 1)/4.> (although in number theory we use a different constant factor).> This shows there are six values of v for which two of the roots> coincide.> By Cardan's formula:> b = ((1-v^3)/2 + sqrt(D))^{1/3} + ((1-v^3)/2 - sqrt(D))^{1/3},> or> a = ((1-v^3)/2 + sqrt(D))^{1/3} + ((1-v^3)/2 - sqrt(D))^{1/3} - v,> | It might be especially interesting to see the result and see what> | happens at v=-1.Readers should note that assuming the above is correct at v=-1, D=0,so you get a = 1^{1/3} + 1^{1/3} + 1which gives you the three a's, a_1=0, a_2=0, a_3=3.Now consider Keith Ramsay's reply. > Because D = (v+1)(1-3v^3)(1+v+v^2)/4, near v=-1, D is approximately> v+1. The two values of sqrt(D) trade places with each other as we> sqrt(D) with -sqrt(D) wouldn't change the value of a. But the two> cube roots are chosen so that at v=-1, for example, they are either> both 1, or one is (-1+sqrt(3)*i)/2 and the other is (-1-sqrt(3)*i)/2,> or the ?st is (-1-sqrt(3)*i)/2 and the other is (-1+sqrt(3)*i)/2.> So changing the sign on the square root of D is equivalent to leaving> the ?st root (where both cube roots are taken to be 1) alone, while> exchanging the other two roots. As I said before, if you take a loop> around v=-1, the value of one of the roots comes back to the value of> the other one.Um, did *anyone* see an answer in there?> | Reminder to readers, Keith Ramsay has brought up a continuity> | question, which actually is irrelevant, but what the hell?> I was trying to convince you that it's unsafe to assume that the> values of a_1, a_2, and a_3 extrapolate in a natural way from one> value of m to another. This would be needed, for example, for a_2> to be always divisible by f or anything like that. Otherwise, how> could it possibly be true that it's one particular one of the three> that has a certain divisibility property, if the manner in which> we've decided which of the three roots to assign to each of the> three variables in an arbitrary way depending on the value of m?> I'm sorry if the relevance doesn't seem clear to you.There is no relevance. In polynomial equations you *can* have itwhere certain roots have a factor while others do not.> The one obvious way to attempt to extrapolate values of a_1, a_2> and a_3 from one value of m to another is by continuity. Given a> path in the complex plane which avoids all the points where two> of the roots coincide, we can see what happens to the a_i if we> continuously change m along that path, while letting the a_i also> change continuously as we go. Unfortunately (or fortunately,> actually) which a_i is which when we reach the end of the path> will depend upon which path we took from one endpoint to the other.> So if I have a given value of a at m=0 (say a=0), the question of> which of the three values at m=1 corresponds to it is meaningless> unless I make an arbitrary convention.Actually you simply take the three values of the cuberoot operator,just like with square roots you take the two values of the square rootoperator.For those who are confused simply remember that x^3 - 1 = 0, gives youthree values for x.> That's essentially what prevents them from being continuous> everywhere.Looks to me like you put down a lot of words Keith Ramsay, yet somehowmanaged to not even refer back to a = ((1-v^3)/2 + sqrt(D))^{1/3} + ((1-v^3)/2 - sqrt(D))^{1/3} - vfrom your work before.> I don't have the time today, but what one can do is to show that> for each epsilon>0, there exists a delta>0 having the property that> if |v+1| < delta, then one of the roots is within epsilon of the> nonzero root at v=-1 (what was it, a=1?), while the other two satisfy> |a^2/(v+1) - C| < epsilon where C is some constant (probably just 1).> Then we can consider the values v = -1+e^{it}. For small epsilon,> the inequality forces a/e^{it/2} to be close to one of the square> roots of C. Then we can carry out the same argument as last time> but with the two sets being the t for which |a/e^{it/2} - sqrt(C)|> is smaller and the t for which |a/e^{it/2} + sqrt(C)| is smaller.Well, if you don't have the time it's not really worth mentioning, nowis it?After all, the discussion isn't a political one, and you're NOT on FoxNews!!!> [...]> | So you're admitting to bringing up what I've called irrelevant issues> | without having actually checked them, while refusing to fully> | acknowledge the mathematical argument in the paper including a rather> | basic lemma that you simply don't mention.> I ?d the lemma very uninteresting. I don't understand how you> manage to think of it as important.That lemma is the linchpin of the paper!!!> Similar to a lot of arguments written by undergraduate math majors> early in their studies, this argument plods its way slowly through> the routine parts of the argument, but condenses into a rapid sprint> the part which is most in need of explanation, and also hardest to> believe.Your belief here is irrelevant as a proof begins with a truth thenproceeds by logical steps to a conclusion which then must be true. Challenging a paper requires that you ?d that it did not begin witha truth, or that you ?d a break in the logical chain.James Harris === >> > Remember (unlike e.g. the Gaussian integers) the algebraic integers> are dense in the complex plane, meaning that any circle, no matter> how small, has algebraic integers inside it.>>Hmmm...interesting assertion, but what about singularities?> I'll bite. What about singularities?> We aren't talking about a function here, just about two sets, the>> complex numbers and the algebraic integers. There aren't any>> singularities. And if there were, what does that have to do with>> whether there are in?itely many algebraic integers everywhere you>> look?>> >>A singularity is a circle of 0 radius,No, it's not. A singularity is a property of a function. And intopological statements like a circle, no matter how small, it isunderstood that the term circle refers to a ?ite radius.> and in the complex plane I can>pick an in?ite number of fractions.What does that have to do with the statement? The statement is this:Pick a complex value z. Pick a radius epsilon >0. The neighborhood {win C: |z - w| < epsilon} has in?itely many algebraic integers in it.What the heck does I can pick an in?ite number of fractions haveto do with the density of algebraic integers?Within a radius of 0.01 of 1 + i there are an in?ite number ofalgebraic integers.Within a radius of 0.00002 of -sqrt(3) + i*pi there are an in?itenumber of algebraic integers.What does I can pick an in?ite number of fractions have to do withstatements like those? - Randy === yeah, but a circle of no radius would have itselfas a singularity. did we uncover a new property/axiom/pedagogical twist?otherwise, Buddy,a ring is what I say it is, now; capiche? > No, it's not. A singularity is a property of a function. And in> topological statements like a circle, no matter how small, it is> understood that the term circle refers to a ?ite radius.--A church-school McCrusade (Blair's ideals?):Harry-the-Mad-Potter want's US to kill Iraqis?... http://www.tarpley.net/bush25.htm (Thyroid Storm ch.) http://www.rwgrayprojects.com/synergetics/plates/plates.html http://quincy4board.homestead.com/?es/curriculum/Cosmo.PCX== ==I'm trying to ?ure out how to correctly form the logical negation ofthis sentence:For all real numbers satisfying a= b),(forall n in N):(a+1/n >= b)i.e. There exist real numbers satisfying a>=b, such that for allnatural numbers n, a+1/n >= b.However, I am obviously doing something wrong in the negation, sinceBOTH of the above sentences appear to be true, and by the law ofexcluded middle, P and not P cannot BOTH be true.So, what am I doing wrong?thanks. === > I'm trying to ?ure out how to correctly form the logical negation of> this sentence:> For all real numbers satisfying a such that a + 1/n < b.> Converting this sentence into symbolic form gives something like:> (forall a,b in R ):( a < b),(exists n in N):( a+1/n and then forming the negation, I have> (exists a,b in R):(a>= b),(forall n in N):(a+1/n >= b)> i.e. There exist real numbers satisfying a>=b, such that for all> natural numbers n, a+1/n >= b.> However, I am obviously doing something wrong in the negation, since> BOTH of the above sentences appear to be true, and by the law of> excluded middle, P and not P cannot BOTH be true.> So, what am I doing wrong?Your original statement says that if there are two reals, a and b with a < b, there exists n such that a + 1/n < b.The negation of that would be that there exist two reals, a and b, with a < b, such that for all n, a + 1/n >= b.I think you got into trouble when you swapped a < b for a >= b in your attempted negation. === > For all real numbers satisfying a such that a + 1/n < b.>> Converting this sentence into symbolic form gives something like:> (forall a,b in R ):( a < b),(exists n in N):( a+1/n for all a,b in R, (a < b ==> some n in N with a+1/n < b)> and then forming the negation, I have> (exists a,b in R):(a>= b),(forall n in N):(a+1/n >= b)>some a,b in R with (a < b and for all n in N, not a+1/n < b)> i.e. There exist real numbers satisfying a>=b, such that for all> natural numbers n, a+1/n >= b.>Archimedean principle for real numbers: for all r in R, some n in N with r < n.if a < b, then b-a /= 0 some n in N with 1/(b-a) < n 1/n < b-a as 0 < b-a a + 1/n < a + b-a = b> So, what am I doing wrong?You converted wrong and you may have used ~(p&q) <-> (~p&~q)instead of ~(p&q) <-> (~p v ~q)when forming the negation. === > I'm trying to ?ure out how to correctly form the logical negation of> this sentence:> For all real numbers satisfying a such that a + 1/n < b.The tricky part here is the phrase satisfying a < b.Actually, the same problem applies to the phrase real also,except that real is a unary relation, while a < b is abinary relation.That is, strictly, you can use only for all x and notfor all real x, etc. That is, the phrase for all real xis an abreviation for the phrase for all x,... (if x is real,then ...).Note that you can swap (for all real a)(for all real b) toget (for all real b)(for all real a) with no problem.But, you can not swap (for all real a)(for all real b with a < b)to get (for all real b with a < b)(for all real a) sincethe ?st a is then left unquanti?d.> Converting this sentence into symbolic form gives something like:> (forall a,b in R ):( a < b),(exists n in N):( a+1/n and then forming the negation, I have> (exists a,b in R):(a>= b),(forall n in N):(a+1/n >= b) (for some a in R)(for some b in R)(for all n in N) ((a < b) and (a + 1/n >= b))> i.e. There exist real numbers satisfying a>=b, such that for all> natural numbers n, a+1/n >= b.You should not have negated a However, I am obviously doing something wrong in the negation, since> BOTH of the above sentences appear to be true, and by the law of> excluded middle, P and not P cannot BOTH be true.> So, what am I doing wrong?Eliminating a in R etc in the phrase for a in R, I have: (for all a)(for all b)(for some n) (if a in R and b in R and n in N and a < b then a + 1/n < b)Try negating that and see that a in R remains and does notbecome a not in R.Or, even better, since I don't like the phrase a < b unlessI de?itely already know that a and b are real numbers, I supposethat the above should be written: (for all a)(for all b)(for some n) (if a in R and b in R and n in N, then if a < b then a + 1/n < b)You could try and negate that also. I didn't do it myself.I hope it works out ok.-- Bill Hale === >I'm trying to ?ure out how to correctly form the logical negation of>this sentence:>For all real numbers satisfying asuch that a + 1/n < b.>Converting this sentence into symbolic form gives something like:>(forall a,b in R ):( a < b),(exists n in N):( a+1/n exists n in N (a + 1/n < b))>and then forming the negation, I have>(exists a,b in R):(a>= b),(forall n in N):(a+1/n >= b)Nope. The negation is (exists a,b in R) ~(a < b --> exists n in N (a + 1/n < b)).Since ~(p --> q) is p & ~q, the desired negation is (exists a,b in R) (a < b & ~exists n in N (a + 1/n < b)),or, ?ally, (exists a,b in R) (a < b & forall n in N (a + 1/n >= b)).[...]Brian === [cut]> Eliminating a in R etc in the phrase for a in R, I have:> (for all a)(for all b)(for some n)> (if a in R and b in R and n in N and a < b then a + 1/n < b)I eliminated n in N from the phrase for some n in N wrong.It should be: (for all a)(for all b)(for some n) (n in N and (if a in R and b in R and a < b then a + 1/n < b))-- Bill Hale === >I'm trying to ?ure out how to correctly form the logical negation of>this sentence:>For all real numbers satisfying asuch that a + 1/n < b.For some real numbers ai.e. There exist real numbers satisfying a>=b, such that for all>natural numbers n, a+1/n >= b.This is For some not X, Z. :-)-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/You ?d yourself amusing, Blackadder.I try not to ?the face of public opinion.Mime-version: 1.0 === > I'm trying to ?ure out how to correctly form the logical negation of> this sentence:> For all real numbers satisfying a such that a + 1/n < b.> Converting this sentence into symbolic form gives something like:> (forall a,b in R ):( a < b),(exists n in N):( a+1/n and then forming the negation, I have> (exists a,b in R):(a>= b),(forall n in N):(a+1/n >= b)> i.e. There exist real numbers satisfying a>=b, such that for all> natural numbers n, a+1/n >= b.> However, I am obviously doing something wrong in the negation, since> BOTH of the above sentences appear to be true, and by the law of> excluded middle, P and not P cannot BOTH be true.> So, what am I doing wrong?> thanks.Assuming that your N does not contain 0, consider:(exists a,b in R)(forall n in N):if(a >= b) then (a+1/n >= b)Which negates to:(forall a,b in R)(exists n in N):(a>= b) and (a+1/n < b) === Determine a>0 so that the equationsystem: x^2+y^2=18{ y=-x+ahas exactly one solution.How Do I solve a problem of this kind? === >Determine a>0 so that the equationsystem:> x^2+y^2=18> y=-x+a>has exactly one solution.>>How Do I solve a problem of this kind?Solve the equations simultaneously. Since one is a quadratic, you will end up with some +/- radical expression, and the radicand will probably contain a. Determine a so that the choice of + or - makes no difference, i.e. so that the radicand is 0.-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/You ?d yourself amusing, Blackadder.I try not to ?the face of public opinion. === > Determine a>0 so that the equationsystem:> x^2+y^2=18> {> y=-x+a> has exactly one solution.> How Do I solve a problem of this kind?> To rephrase another answer, substitute a - x into x^2 + y^2 - 18 = 0.Square the a - x and collect things up and you'll have a quadratic.Think of the quadratic formula. The discriminant, the part under thesquare root (b^2 - 4*a*c - this a is not _your_ a) determines howmany solutions there are: if it is zero there is only one so set itequal to zero and solve for a. I get a = 6 (and a = -6.)-- Paul SperryColumbia, SC (USA) === > Determine a>0 so that the equationsystem:> x^2+y^2=18> > {> y=-x+a> has exactly one solution.> How Do I solve a problem of this kind?> To rephrase another answer, substitute a - x into x^2 + y^2 - 18 = 0.> Square the a - x and collect things up and you'll have a quadratic.[snip]That'll all work, but another approach is a little geometryand some trig.x^2 + y^2 = 18 is a circle centered on (0,0) withradius 3sqrt(2). y=-x+a with a>0 is a line with slope -1 thatpasses through quadrants I, II, and IV. Having one solutionmeans the line intersects the circle at only one point, whichmeans it must be tangent to the circle. By the constraintsof the problem, we'll be in quadrant I. In quadrant I, acircle only has slope -1 at the point where x=y. Thatimmediately gives us the point (3,3).So the desired tangent line has slope -1 and passes through(3, 3): y - 3 = (-1)(x - 3) y - 3 = -x + 3 y = -x + 6Thus a=6.-- Rich Carreiro rlcarr@animato.arlington.ma.us === >Determine a>0 so that the equationsystem:>> x^2+y^2=18>{> y=-x+a>>has exactly one solution.>>How Do I solve a problem of this kind?>To rephrase another answer, substitute a - x into x^2 + y^2 - 18 = 0.>>Square the a - x and collect things up and you'll have a quadratic.>> >[snip]>>That'll all work, but another approach is a little geometry>and some trig.>>x^2 + y^2 = 18 is a circle centered on (0,0) with>radius 3sqrt(2). y=-x+a with a>0 is a line with slope -1 that>passes through quadrants I, II, and IV. Having one solution>means the line intersects the circle at only one point, which>means it must be tangent to the circle. By the constraints>of the problem, we'll be in quadrant I. In quadrant I, a>circle only has slope -1 at the point where x=y. That>immediately gives us the point (3,3).>>So the desired tangent line has slope -1 and passes through>(3, 3):> y - 3 = (-1)(x - 3)> y - 3 = -x + 3> y = -x + 6>>Thus a=6.>And avoids the spurious a=-6 solution.This reminds me of one de?ition of a mathematician as someone who will spend two weeks looking for the way to reduce two hours of calculation to 10 minutes. (Actually, I ?st heard that as trick rather than way, but many of the tricks are actually rather useful, more so than a method is a device, used twice would lead you to believe.)My experience has been that very few students appreciate the elegance of this and most view it as a trick. In other words, it's totally inappropriate for classroom use.I wonder what we'll ?d out about Mr. Aspen's mathematical sense.Jon Miller === > Determine a>0 so that the equationsystem:>> x^2+y^2=18> {> y=-x+a>> has exactly one solution.>> How Do I solve a problem of this kind?>>I dont know what more to say! =)Said Aspen === [skip]> Since I explained it the implication that I didn't is false.Since you didn't actually explained anything, the implication is correct.I asked you to explain what *kind* of thing factor g is, and your response was -Not even close. Read the paper. That's not an explanation. === Does James Harris have a degree in math? === > Does James Harris have a degree in math?No. He claims to have an undergraduate degree in physics.-- Wayne Brown | When your tail's in a crack, you improvisefwbrown@bellsouth.net | if you're good enough. Otherwise you give | your pelt to the trapper.e^(i*pi) = -1 -- Euler | -- John Myers Myers, Silverlock === > > I was going back over my work as I often do when I ?ally realized> that my lemma in my paper> Advanced Polynomial Factorization> http://groups.msn.com/AmateurMath/Documents/FactProof.pdf> > was wrong.> I had a factor g of the polynomial P(x) where g = r+c, and r is> supposedly proven to not be coprime to x, when in fact it can be> coprime to x.> What I was actually using for the paper is the fact that r varies with> x, while c remains constant, so I made the simplest change.> > It is possible to prove that r is not coprime to P(x)-P(0), but not> worth the effort here.> My apologies for the error.> In the ?st paragraph you give the wrong roots for x^2+x-5=0. You> might want to correct them, too.> James, I am new to your work. You say: As an example consider> sqrt(x+1) which is a non polynomial factor of x+1. What do you mean> by saying that sqrt(x+1) is a factor of x+1?> John PetersThere are two ways to look at it. Since the ring is algebraicintegers, you can see it as that given x, which is going to be analgebraic integer as that's the ring, sqrt(x+1) is a factor of x+1.For instance with x=2, which is an algebraic integer, sqrt(3) is afactor of 3.The other way to look at it is that x+1 can be considered the resultof the multiplication sqrt(x+1) times sqrt(x+1) equals x+1; therefore,sqrt(x+1) is a factor of x+1, where ring operations allow thatexpression. But they don't allow (x+1)/(y+1) in general as the / isnot allowed in general as division is not a ring operation.So I can also say that given the polynomial P(x)=x+1, sqrt(x+1) is afactor of the polynomial, though you may wonder what to now callsqrt(x+1). I don't care what you call it.Now sure, if you qualify by saying y=x, then y+1 is a factor of x+1 inthe ring, but not, in general, otherwise, if all you know is that y+1is in the ring.Some may see that I don't have to talk speci?ally about polynomialrings or something wackier to handle sqrt(x+1) by taking thisapproach.If you ?d that makes your head swim, you can consider values of x+1from the ?st point of view.James Harris === > ...> sqrt(x+1) is a factor of x+1, where ring operations allow that> ...In _what_ is sqrt(x+1) a factor of x+1?GC === > ...>> sqrt(x+1) is a factor of x+1, where ring operations allow that>> ...>In _what_ is sqrt(x+1) a factor of x+1?I believe this is what JSH means: If x is an algebraic integer, then so is x+1 and sqrt(x+1). Moreover, there is an algebraic integer r (viz. r = sqrt(x+1)) such that r*sqrt(x+1) = x+1. Therefore sqrt(x+1) is a factor of x+1 in the ring of algebraic integers.If this IS what he means, then he is, of course, quite correct. (Oh, GOD! It's ?e o'clock in the morning of midsummer's eve and JSH is starting to make sense!)The problem is that he categorically denies that 2 is a factor of x^2 + x in the ring of integers, so my interpretation may be wrong.-- Thomas Wasell | A great many people think they are thinking when theywasell@bahnhof.se | are merely rearranging their prejudices. | -- William James === >> ...>> sqrt(x+1) is a factor of x+1, where ring operations allow that>> ...> >>In _what_ is sqrt(x+1) a factor of x+1?>> I believe this is what JSH means:>> If x is an algebraic integer, then so is x+1 and sqrt(x+1).Moreover, there> is an algebraic integer r (viz. r = sqrt(x+1)) such that r*sqrt(x+1)= x+1.> Therefore sqrt(x+1) is a factor of x+1 in the ring of algebraicintegers.>> If this IS what he means, then he is, of course, quite correct. (Oh,GOD!> It's ?e o'clock in the morning of midsummer's eve and JSH isstarting to> make sense!)>> The problem is that he categorically denies that 2 is a factor ofx^2 + x> in the ring of integers, so my interpretation may be wrong.James,Building on the insight provided by Thomas, let me frame a possiblede?ition:1) Let S be a set.2) Let f, g and h be [single-valued] functions de?ed on S and takingvalues in S. That is, their domain and codomain are S.3) Let * be a [single-valued] binary operator whose operands areelements of S and which takes values in S.4) Suppose, for all x in S, f(x)*g(x)=h(x).De?ition: In this case we say that f is a factor of h. Or(equivalently) that h is divisible by f.In the case you are interested in, S is the set of algebraic integers,and * is (complex) multiplication.(Note that our sqrt(x+1) example might have some problems becausesqrt(x+1) might not be single-valued.)Is the above de?ition correct?John Peters === > ...>> sqrt(x+1) is a factor of x+1, where ring operations allow that>> ...>In _what_ is sqrt(x+1) a factor of x+1?> > I believe this is what JSH means: > If x is an algebraic integer, then so is x+1 and sqrt(x+1). Moreover, there > is an algebraic integer r (viz. r = sqrt(x+1)) such that r*sqrt(x+1) = x+1. > Therefore sqrt(x+1) is a factor of x+1 in the ring of algebraic integers.> If this IS what he means, then he is, of course, quite correct. (Oh, GOD! > It's ?e o'clock in the morning of midsummer's eve and JSH is starting to > make sense!)> The problem is that he categorically denies that 2 is a factor of x^2 + x > in the ring of integers, so my interpretation may be wrong.That's not true. The original post had something about that being inthe same sense if I remember correctly. So you left off keyinformation in your claim.After all, in the ring of algebraic integers, 2 is NOT in general afactor of x^2 + x.For instance, with x=(1+sqrt(-3))/2, x^2 + x = sqrt(-3).That it is in the ring of integers is, in my mind, trivia, which isnot in the same sense as something like x being a factor of x^2 + x,which IS true in the ring of algebraic integers, so it's NOT in thesame sense.What I've seen time and time again is a grasping at any little commentof mine to try and see someway to make it not make sense.Here when I talk of factorizations in what I think is a rather obviousway, bringing up a trivial result in the ring of integers as if it hasgreat sign?ance just makes me wonder.Don't ANY of you care about what the truth is? Don't bother me with trivia. James Harris === nevermind. let's start another item!> I had a factor g of the polynomial P(x) where g = r+c, and r is> supposedly proven to not be coprime to x, when in fact it can be> coprime to x.> ...> > Or r can be constant and 0.> What you fail to state anywhere is how g is restricted. Or is it> unrestricted? If unrestricted:> g(x) = def: 1 (if x = 0), x + 5 (elsewhere)> g(x) is a factor of P(x) = x + 5 in the sense you state. What are r and c?--les ducs d'Enron! http://quincy4board.homestead.com/ Funny.html (schoolboard stuf?') === > The problem is that he categorically denies that 2 is a factor of x^2 + x > in the ring of integers, so my interpretation may be wrong.> That's not true. The original post had something about that being in> the same sense if I remember correctly. So you left off key> information in your claim.> After all, in the ring of algebraic integers, 2 is NOT in general a> factor of x^2 + x.> For instance, with x=(1+sqrt(-3))/2, x^2 + x = sqrt(-3).> But, 2 IS a factor of sqrt(-3), the other factor being sqrt(-3)/2,which is a root of 4x^2+3, hence algebraic. === [snip]>But, 2 IS a factor of sqrt(-3), the other factor being sqrt(-3)/2,>which is a root of 4x^2+3, hence algebraic.But it's not an algebraic *integer*. I.e. it's not the root of a *monic* polynomial.-- Thomas Wasell | For a man to truly understand rejection, he must ?stwasell@bahnhof.se | be ignored by a cat. === > [snip]> >But, 2 IS a factor of sqrt(-3), the other factor being sqrt(-3)/2,>which is a root of 4x^2+3, hence algebraic.> But it's not an algebraic *integer*. I.e. it's not the root of a *monic* > polynomial.I'm just playing by the same rules that James does --a polynomial isan algebraic integer,a function,an integer,a square root,a ring of polynomials,a real number,a ring of algebraic integers,a monic polynomial,a complex number,a transcendental function,a Laplace Transform, a ...Hell, no wonder math is full of contradictions! === ... a buncha crap ...> What I've seen time and time again is a grasping at any little comment> of mine to try and see someway to make it not make sense.> Here when I talk of factorizations in what I think is a rather obvious> way, bringing up a trivial result in the ring of integers as if it has> great sign?ance just makes me wonder.> Don't ANY of you care about what the truth is? > Apparently more than you do. Note this:De?e the polynomials q(x) = 8 x^2 - 76 x -185 r(x) = 8 x^2 - 4 x - 45 s(x) = 4 x^2 - 37 x - 104Then for z any root of the polynomial p(x) = x^3 - 12 x^2 + 65,we have q(z)*r(z) = 5 r(z)*s(z) = z.By virtue of the polynomials q,r,s having integer coef?ients, andof z being a root of p(x), we know that z, q(z), r(z), and s(z) are allalgebraic integers.Finally, the minimal polynomial for r(z) is MinPoly(r(z)) = x^3 - 969 x^2 + 315 x + 5The divisibility properties were veri?d in Maxima; the minimalpolynomial was provided by KASH, and veri?d in KASH.Your claim regarding the properties of the coef?ients ai inthe factorization: 65 x^3 - 12 x + 1 = (a1 x + 1)(a2 x + 1)(a3 x + 1)namely, that ONE of the ai's is coprime to 5, is clearlyincorrect. Therefore, your argument is ?Once again, your methods are shown to produce incorrectresults, despite your con?ence in your own ability tospot correct logic. Your logic, your methods, your graspof mathematics are *all* unsound.> Don't bother me with trivia. > How trivial was that?Score: sci.math omega JSH nullset> James HarrisDale. === John Peters skrev i melding> ...>> sqrt(x+1) is a factor of x+1, where ring operations allow that>> ...>>In _what_ is sqrt(x+1) a factor of x+1?>> I believe this is what JSH means:>> If x is an algebraic integer, then so is x+1 and sqrt(x+1).> Moreover, there> is an algebraic integer r (viz. r = sqrt(x+1)) such that r*sqrt(x+1)> = x+1.> Therefore sqrt(x+1) is a factor of x+1 in the ring of algebraic> integers.>> If this IS what he means, then he is, of course, quite correct. (Oh,> GOD!> It's ?e o'clock in the morning of midsummer's eve and JSH is> starting to> make sense!)>> The problem is that he categorically denies that 2 is a factor of> x^2 + x> > in the ring of integers, so my interpretation may be wrong.>> James,>> Building on the insight provided by Thomas, let me frame a possible> de?ition:>> 1) Let S be a set.>> 2) Let f, g and h be [single-valued] functions de?ed on S and taking> values in S. That is, their domain and codomain are S.>> 3) Let * be a [single-valued] binary operator whose operands are> elements of S and which takes values in S.>> 4) Suppose, for all x in S, f(x)*g(x)=h(x).>> De?ition: In this case we say that f is a factor of h. Or> (equivalently) that h is divisible by f.>> In the case you are interested in, S is the set of algebraic integers,> and * is (complex) multiplication.>> (Note that our sqrt(x+1) example might have some problems because> sqrt(x+1) might not be single-valued.)Isn't sqrt(a) single-valued? Don't mistake it to be +/- ,because it isn't.Sqrt is allways positive! It follows from the de?ition of Sqrt.>> Is the above de?ition correct?>> John Peters>> === don't bother me with mathematics, jerk. now, let's start another item! > By virtue of the polynomials q,r,s having integer coef?ients, and> of z being a root of p(x), we know that z, q(z), r(z), and s(z) are all> algebraic integers.> Finally, the minimal polynomial for r(z) is> MinPoly(r(z)) = x^3 - 969 x^2 + 315 x + 5> The divisibility properties were veri?d in Maxima; the minimal> polynomial was provided by KASH, and veri?d in KASH.> Your claim regarding the properties of the coef?ients ai in> the factorization:> 65 x^3 - 12 x + 1 = (a1 x + 1)(a2 x + 1)(a3 x + 1)> namely, that ONE of the ai's is coprime to 5, is clearly--Dec.2000 ?WAND' Chairman Paul O'Neill, reelectedto Board. Newsish?http://www.rand.org/publications/randreview/issues/rr .12.00/http://members.tripod.com/~american_almanac === I'm living in HK. We had one of the biggest rally against the HK gov't since the June 4th ?89 incident. The press reported that there are 500K peoplewent to the street for the protest.I'm very interested with the reported ?ures. Is there really a 'reasonable' method based on statistical model to approximate the total no. ofprotesters with acceptable degree of con?ence? Can anyone show me the concept. === >I'm living in HK. We had one of the biggest rally against the HK gov't since the June 4th ?89 incident. The press reported that there are 500K people>went to the street for the protest.>>I'm very interested with the reported ?ures. Is there really a 'reasonable' method based on statistical model to approximate the total no. of>protesters with acceptable degree of con?ence? Can anyone show me the concept.>I Have Been Told (tm) that no one estimating crowd sizes uses any reasonable method to estimate them. I don't remember the reference.The way to estimate crowd size is the same as the one astronomers use to estimate the number of visible stars. You pick a small area of surveillance, ?d the volume of space that area views, actually count the number of people/stars/whatever. Then pick another area and repeat. You need to use statistical sampling methodology to assure that your samples are representative of the total population. You can get quite sophisticated with this, so that your efforts are concentrated in the areas with the most importance/dif?ulty/whatever. So for crowds, you'd probably concentrate your efforts at dense points, rather than along the edges. Then you average (possibly with weights) your observations to get an average density, and then multiply that by the volume to get the total number. Of course, for crowds you'd use surface area instead of volume, but you get the same idea.I have done this, but if your interest isn't in the results (that is, if BigNum crowds in headlines sell newspapers/support your political point of view/etc. and accuracy isn't really relevant) it's probably not worth the effort.At some time, someone will probably add a fairly simple routine to the camera analysis software to have crowd size printed out in the automatically generated report, but that's at least a couple of years down the road. http://www.ohio.com/mld/ohio/news/6211959.htm I'm guessing that deployment of the CTS software/hardware will take a couple of years to implement, and crowd size estimation will be low enough priority that they just don't get around to it.So they won't be able to tell you how many people are in the crowd, but they'll be able to give you all their names. Well, there's another method: just count the number of names in the list of attendees. Maybe it won't take a couple of years.Jon Miller === Jon/Mary,The methodology you mentioned, does it make a assumption that the crowd in question is stationary just like the stars in the clear sky? My scenario isthe crowd to be measured has varied mobility (e.g. the crowd is moving at non-constant speed at one direction). When the crowd moves forward, newin-coming crowd comes in and it took 7 hours to travel from Point A to Point B.I'm just thinking of differential equations to solve it. Does it make sense?James>I'm living in HK. We had one of the biggest rally against the HK gov't since the June 4th ?89 incident. The press reported that there are 500K people>>went to the street for the protest.>>I'm very interested with the reported ?ures. Is there really a 'reasonable' method based on statistical model to approximate the total no. of>>protesters with acceptable degree of con?ence? Can anyone show me the concept.>I Have Been Told (tm) that no one estimating crowd sizes uses any >reasonable method to estimate them. I don't remember the reference.>>The way to estimate crowd size is the same as the one astronomers use to >estimate the number of visible stars. You pick a small area of >surveillance, ?d the volume of space that area views, actually count >the number of people/stars/whatever. Then pick another area and repeat. > You need to use statistical sampling methodology to assure that your >samples are representative of the total population. You can get quite >sophisticated with this, so that your efforts are concentrated in the >areas with the most importance/dif?ulty/whatever. So for crowds, >you'd probably concentrate your efforts at dense points, rather than >along the edges. Then you average (possibly with weights) your >observations to get an average density, and then multiply that by the >volume to get the total number. Of course, for crowds you'd use surface >area instead of volume, but you get the same idea.>>I have done this, but if your interest isn't in the results (that is, if >BigNum crowds in headlines sell newspapers/support your political point >of view/etc. and accuracy isn't really relevant) it's probably not worth >the effort.>>At some time, someone will probably add a fairly simple routine to the >camera analysis software to have crowd size printed out in the >automatically generated report, but that's at least a couple of years >down the road. http://www.ohio.com/mld/ohio/news/6211959.htm I'm >guessing that deployment of the CTS software/hardware will take a couple >of years to implement, and crowd size estimation will be low enough >priority that they just don't get around to it.>>So they won't be able to tell you how many people are in the crowd, but >they'll be able to give you all their names. Well, there's another >method: just count the number of names in the list of attendees. Maybe >it won't take a couple of years.>>Jon Miller === > The methodology you mentioned, does it make a assumption that the crowd> in question is stationary just like the stars in the clear sky? My> scenario is the crowd to be measured has varied mobility (e.g. the crowd> is moving at non-constant speed at one direction). When the crowd moves> forward, new in-coming crowd comes in and it took 7 hours to travel from> Point A to Point B.>No, it makes sense to photograph crowd from satellite, plane orhellicopter perhaps several times to assure estimation of peak event.However, these times, as protests are ignored, crowd estimates aren'tneeded nor event and attendance deemed news wirthy.> I'm just thinking of differential equations to solve it. Does it make sense?No, renting a plane and an aerial survey camara does. === >In alt.math.undergrad you write:>At some time, someone will probably add a fairly simple routine to the >>camera analysis software to have crowd size printed out in the >>automatically generated report, but that's at least a couple of years >>down the road.>I recall some press release from a company that I think was dealing with>designing places for selling tickets, handling crowds, that sort of thing, >and if I'm not confused, I think they had done substantial work on counting>automatically with cameras. But it has been a while and I'm not able to>think of any of the keywords that might turn this up.>Could be. Now that I think about it, I think the discussion I read was about the size of the crowd at the Million Man March, so my info is certainly dated.I guess I'll post this to alt.math.undergrad since it's relevant, and I don't mind appearing stupid (I have children, so it happens all the time Jon Miller === Market research for a new mobile phone suggests that the potential markethas a ceiling of 40 million units and that 0 sales will be achieved withoutmarketing. After spending 1 million on marketing 20 million sales wererecorded.Can anyone model for sales (S) in terms of advertising expenditure (x) ofthe form:S = a+(be)POWER-cx === > Market research for a new mobile phone suggests that the potential market> has a ceiling of 40 million units and that 0 sales will be achieved without> marketing. After spending 1 million on marketing 20 million sales were> recorded.> Can anyone model for sales (S) in terms of advertising expenditure (x) of> the form:> S = a+(be)POWER-cxI assume you mean S = a + b e^(-cx)Well, you have some known values, so use them: (0, 0) (+oo, 40mil) (1mil, 20 mil)Plug those (x, S) pairs into the equation for S and see what theyimply about constants a, b, and c.-- Rich Carreiro rlcarr@animato.arlington.ma.us === >>Market research for a new mobile phone suggests that the potential market>>has a ceiling of 40 million units and that 0 sales will be achieved without>>marketing. After spending 1 million on marketing 20 million sales were>>recorded.>>Can anyone model for sales (S) in terms of advertising expenditure (x) of>>the form:>>S = a+(be)POWER-cx> I assume you mean> S = a + b e^(-cx)> Well, you have some known values, so use them:> (0, 0)> (+oo, 40mil)> (1mil, 20 mil)> Plug those (x, S) pairs into the equation for S and see what they> imply about constants a, b, and c.> === Let's say I have a function, f(x), whose inverse for some reason I can'tcalculate. Can I use the formula:g(x) = f^(-1)(x)g'(x) = 1 / [ f'(g(x)) ]so ?d f^(-1)(x) explicitly? If so, can I always ?d it?Also, does every function whose inverse can be expressed in terms of a?ite number of elementary operations be expressed in terms of a ?itenumber of elementary operations? Also, is it possible to have a functionthat can't be expressed in terms of a ?ite number of elementary operationshave an inverse that can be?Jeremy === > Let's say I have a function, f(x), whose inverse for some reason I can't> calculate. Can I use the formula:>> g(x) = f^(-1)(x)> g'(x) = 1 / [ f'(g(x)) ]>g(x) = integral g'(x) dx = integral 1/f'(g(x)) dxlet u = g(x) = integral du/f'(u)g'(x) = integral du = u = g(x)> so ?d f^(-1)(x) explicitly? If so, can I always ?d it?>Let's test it out. For n > 5 letf(x) = sum(i=0..n) x^i restricted to some interval where it's 1-1g'(x) = 1/sum(i=1..n) i.g(x)^(i-1)What's used for g(x) to calculate this sum?> Also, does every function whose inverse can be expressed in terms of a> ?ite number of elementary operations be expressed in terms of a ?ite> number of elementary operations?> Also, is it possible to have a function that can't be expressed in terms> of a ?ite number of elementary operations have an inverse that can be?Basically these two questions are the same.Let g be the inverse of f as given above.Can g be expressed in a ?ite number of elementary operations? === > Let's say I have a function, f(x), whose inverse for some reason I can't> calculate. Can I use the formula:> g(x) = f^(-1)(x)> g'(x) = 1 / [ f'(g(x)) ]> so ?d f^(-1)(x) explicitly? If so, can I always ?d it? [...]Do you mean, by integrating 1 / (f'(g(x)) explicitly? I don't see howyou can do the integration without knowing what g(x) is, unless you wantto solve an integral equation. (And the way to solve that particularintegral equation will probably involve ?ding the inverse of f(x) ?st.) -- Christopher Heckman === > Do you mean, by integrating 1 / (f'(g(x)) explicitly? I don't see how> you can do the integration without knowing what g(x) is, unless you want> to solve an integral equation. (And the way to solve that particular> integral equation will probably involve ?ding the inverse of f(x)?st.)Not necessarily by doing it explicitly, but maybe by doing something moreclever than I can think of, or by ?ding a method to solve the differentialequation, or at least do something good to aid in the ?ding of f^(-1)(x).- Jeremy === > so ?d f^(-1)(x) explicitly? If so, can I always ?d it?>> Let's test it out. For n > 5 let> f(x) = sum(i=0..n) x^i restricted to some interval where it's 1-1> g'(x) = 1/sum(i=1..n) i.g(x)^(i-1)> What's used for g(x) to calculate this sum?I'm confused on what you're doing here.> Also, does every function whose inverse can be expressed in terms of a> ?ite number of elementary operations be expressed in terms of a ?ite> number of elementary operations?>> Also, is it possible to have a function that can't be expressed in terms> of a ?ite number of elementary operations have an inverse that can be?>> Basically these two questions are the same.> Let g be the inverse of f as given above.> Can g be expressed in a ?ite number of elementary operations?I would guess so, but I'm confused as how to prove it.- Jeremy === > Let's say I have a function, f(x), whose inverse for some reason I can't> calculate. Can I use the formula:>> g(x) = f^(-1)(x)>> g'(x) = 1 / [ f'(g(x)) ]>> so ?d f^(-1)(x) explicitly? If so, can I always ?d it?>> Also, does every function whose inverse can be expressed in terms of a> ?ite number of elementary operations be expressed in terms of a ?ite> number of elementary operations? Also, is it possible to have a function> that can't be expressed in terms of a ?ite number of elementaryoperations> have an inverse that can be?>> Jeremy>>Suppose I want to ?d the inverse off(x) = e^x + x - 1x = e^y + y - 1 swap variables1 = (e^y)y' + y' take the derivative of both sidesy' = 1/(e^y + 1) solve for y'y'' = .....y^(p) = ...note that when y=1, x = e so y(e) = 1(if y=g(x), then y(e)= g(e) = 1)The Taylor expression becomes,y = 1 + y'(e) (x-e)+y''(e) (x-e)^2 /2! + ...swapping back variables leads to the inverse,so yes, implicit differentation can be used. === >> so ?d f^(-1)(x) explicitly? If so, can I always ?d it?>> Let's test it out. For n > 5 let> f(x) = sum(i=0..n) x^i restricted to some interval where it's 1-1> g'(x) = 1/sum(i=1..n) i.g(x)^(i-1)> What's used for g(x) to calculate this sum?> I'm confused on what you're doing here.As you clipped the orginal problem, I'm limited to general description.How would you like it if I clipped down to ?What's used ... ?I'm taking the function f(x) as I described and applying your clippedformula to it to point out the circularity of your attempt and to giveexample for later.> Also, does every function whose inverse can be expressed in terms of a> ?ite number of elementary operations be expressed in terms of a ?ite> number of elementary operations?>> Also, is it possible to have a function that can't be expressed in terms> of a ?ite number of elementary operations have an inverse that can be?>> Basically these two questions are the same.> Let g be the inverse of f as given above.> Can g be expressed in a ?ite number of elementary operations?>> I would guess so, but I'm confused as how to prove it.>It depends upon what you mean as elementary. For starters there's Abel'sfamous theorem that a polynomial of degree greater than 4 can't be solvedby radicals. Indeed prior to his time, the solution for quartics was thebig ado. === > Let's say I have a function, f(x), whose inverse for some reason I can't> calculate. Can I use the formula:> g(x) = f^(-1)(x)> g'(x) = 1 / [ f'(g(x)) ]> so ?d f^(-1)(x) explicitly? If so, can I always ?d it?> Also, does every function whose inverse can be expressed in terms of a> ?ite number of elementary operations be expressed in terms of a ?ite> number of elementary operations? Also, is it possible to have a function> that can't be expressed in terms of a ?ite number of elementary operations> have an inverse that can be?> JeremyMore on the subject that you want to know is contained is the book byfamous British mathematician G.H. Hardy The integration of functionsof a single variable Hafner, New York, 1971A formula due to J. L. Liouville uses inverse function to ?d aprimitive function of a function.Say that you want to integrate f(x) Int[f(x)]dx = Int[x'*f(x)]dx {Since x is 1} (A)Now since f^-1(f(x)) = x, then x' = (f^-1(f(x)))' then (A) is equal to: Int[f(x)]dx = Int[(f^-1(f(x)))'*f(x)]dx {using partial integration} = f^-1(f(x))*f(x) - Int[f^-1(f(x))*f'(x)]dx = x*f(x) - Int[(F^-1(f(x)))'dx] = x*f(x) - F^-1(f(x))where F^-1 is primitive of f^-1This is because f^-1(f(x))*f'(x) = [F^-1(f(x))]' f^-1(f(x))*f'(x)For example if f(x) = ln(x), x > 0, the above forumula gives:Int[ln(x)]dx = x*ln(x) - exp(ln(x)) + C = x[ln(x) - 1] + CSince primitive of exp(x) is exp(x) + C/Marko === Wow, thanks, I'll have to look into that further! === A quick question: Is every ?ite 2-generated abelian group, i.e. G =< x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seemsso (since such a G can be displayed in a lattice just like one woulduse to visually represent Z_a x Z_b, and there must be relations ofthe form mx=0 for some m, ny=0 for some n), but I'm not 100% certainone way or the other.BDG === > A quick question: Is every ?ite 2-generated abelian group, i.e. G => < x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seems> so (since such a G can be displayed in a lattice just like one would> use to visually represent Z_a x Z_b, and there must be relations of> the form mx=0 for some m, ny=0 for some n), but I'm not 100% certain> one way or the other.> BDGIf you mean G is isomorphic to the direct sum of at most twonon-trivial cyclics the answer is yes.If you mean G is isomorphic to the direct sum of _exactly_ twonon-trivial cyclics then the answer is no: Z_5 = < 2, 3 >.One way to prove the former is to note that G is the homorphic image ofZ x Z and the kernel is of the form K x H with K <= Z x {0} and H <= {0} x Z.-- Paul SperryColumbia, SC (USA) === > A quick question: Is every ?ite 2-generated abelian group, i.e. G => < x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seems> so (since such a G can be displayed in a lattice just like one would> use to visually represent Z_a x Z_b, and there must be relations of> the form mx=0 for some m, ny=0 for some n), but I'm not 100% certain> one way or the other.> BDG> If you mean G is isomorphic to the direct sum of at most two> non-trivial cyclics the answer is yes.> If you mean G is isomorphic to the direct sum of _exactly_ two> non-trivial cyclics then the answer is no: Z_5 = < 2, 3 >.> One way to prove the former is to note that G is the homorphic image of> Z x Z and the kernel is of the form K x H with K <= Z x {0} and > H <= {0} x Z.If we adopt Z_1={0} then apparently everything is OK, Isn't it?Alireza Abdollahi === > A quick question: Is every ?ite 2-generated abelian group, i.e. G =>> < x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seems>> so (since such a G can be displayed in a lattice just like one would>> use to visually represent Z_a x Z_b, and there must be relations of>> the form mx=0 for some m, ny=0 for some n), but I'm not 100% certain>> one way or the other.> BDG>>If you mean G is isomorphic to the direct sum of at most two>non-trivial cyclics the answer is yes.>>If you mean G is isomorphic to the direct sum of _exactly_ two>non-trivial cyclics then the answer is no: Z_5 = < 2, 3 >.But Z_5 = Z_5 x Z_1, so the answer to his question is still yes.An even more trivial special case is < 1, 1 > = Z_1 x Z_1.Derek Holt.>One way to prove the former is to note that G is the homorphic image of>Z x Z and the kernel is of the form K x H with K <= Z x {0} and >H <= {0} x Z.>>-- >Paul Sperry>Columbia, SC (USA) === > A quick question: Is every ?ite 2-generated abelian group, i.e. G =>> < x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seems>> so (since such a G can be displayed in a lattice just like one would>> use to visually represent Z_a x Z_b, and there must be relations of> >> the form mx=0 for some m, ny=0 for some n), but I'm not 100% certain>> one way or the other.> BDG>>If you mean G is isomorphic to the direct sum of at most two> >non-trivial cyclics the answer is yes.>>If you mean G is isomorphic to the direct sum of _exactly_ two>non-trivial cyclics then the answer is no: Z_5 = < 2, 3 >.> But Z_5 = Z_5 x Z_1, so the answer to his question is still yes.Or no. (As far as I'm concerned, Z_1 is trivial.)[...]-- Paul SperryColumbia, SC (USA) === > A quick question: Is every ?ite 2-generated abelian group, i.e. G => < x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seems>> >> so (since such a G can be displayed in a lattice just like one would> use to visually represent Z_a x Z_b, and there must be relations of> the form mx=0 for some m, ny=0 for some n), but I'm not 100% certain> one way or the other.>>If you mean G is isomorphic to the direct sum of at most two>>non-trivial cyclics the answer is yes.>>If you mean G is isomorphic to the direct sum of _exactly_ two>> >non-trivial cyclics then the answer is no: Z_5 = < 2, 3 >.>> But Z_5 = Z_5 x Z_1, so the answer to his question is still yes.>Or no. (As far as I'm concerned, Z_1 is trivial.)The answer to his question as he asked it is ?yes'; you're addinga condition that wasn't part of the question.Brian === >> A quick question: Is every ?ite 2-generated abelian group, i.e. G => < x, y >, isomorphic to Z_a x Z_b for some integers a and b? It seems> so (since such a G can be displayed in a lattice just like one would> use to visually represent Z_a x Z_b, and there must be relations of> the form mx=0 for some m, ny=0 for some n), but I'm not 100% certain> one way or the other.> BDG>>If you mean G is isomorphic to the direct sum of at most two>>non-trivial cyclics the answer is yes.>>If you mean G is isomorphic to the direct sum of _exactly_ two>>non-trivial cyclics then the answer is no: Z_5 = < 2, 3 >.> But Z_5 = Z_5 x Z_1, so the answer to his question is still yes.>Or no. (As far as I'm concerned, Z_1 is trivial.)But the answer to *his* question is yes (since 1 is an integer).Derek Holt. === Let A and B be nonempty subsets of R which are bounded above. Alsode?e the following sets of upper bounds for A and B:S_A : = {s in R : forall a in A, a <= s}S_B : = {s in R : forall b in B, b <= s}I want to ?d formal (rigorous) justi?ation for the following: B subseteq A --> S_A subseteq S_BIn words: If B is a subset of A, then the set of upper bounds for Ais a subset of the set of upper bounds for B.I can easily see that this is true by drawing a picture, but I wouldlike to have formal justi?ation, starting from the de?tions ofsubset and upper bound. Any takers? thanks. === > Let A and B be nonempty subsets of R which are bounded above. Also> de?e the following sets of upper bounds for A and B:> S_A : = {s in R : forall a in A, a <= s}> S_B : = {s in R : forall b in B, b <= s}> I want to ?d formal (rigorous) justi?ation for the following:> B subseteq A --> S_A subseteq S_B> In words: If B is a subset of A, then the set of upper bounds for A> is a subset of the set of upper bounds for B.> I can easily see that this is true by drawing a picture, but I would> like to have formal justi?ation, starting from the de?tions of> subset and upper bound. Any takers? thanks.Let x be a member of S_A. By de?ition of S_A we have a <= x for all elements a of A. As B is a subset of A, every element b of B is also an element of A, and therefore b <= x. So for every element b of B we have b <= x, which means by de?ition of S_B that x is an element of S_B. As x was an arbitrary member of S_A, we have shown that every element of S_A is also an element of S_B, which means that S_A is a subset of S_B. By the way, the upper bound is irrelevant. Every relation between a and s in the de?itions of S_A and S_B would work exactly in the same way. === I have a question concerning ?ite-state machines (FSM). I need toshow that no FSM with input and output set {0, 1} outputs a 1 wheneverthe number of ones and zeros input are equal and 0 otherwise.In my attempt of constructing such an FSM, I ran into a problem. Itseems that the number of states required for a particular input stringis not the same for all input strings. I then ?ured the proof wouldbe by contradiction involving the size of the set of states of theFSM. However, I haven't had luck in developing any rigorous argumentto convince myself of such. Any clues or suggestions?Bernd === > I have a question concerning ?ite-state machines (FSM). I need to> show that no FSM with input and output set {0, 1} outputs a 1 whenever> the number of ones and zeros input are equal and 0 otherwise.> In my attempt of constructing such an FSM, I ran into a problem. It> seems that the number of states required for a particular input string> is not the same for all input strings. I then ?ured the proof would> be by contradiction involving the size of the set of states of the> FSM. However, I haven't had luck in developing any rigorous argument> to convince myself of such. Any clues or suggestions?The important thing to know is how many ahead (or behind) the 1s areon the 0s. At every stage of reading a string, this is some numbern. Can the machine be in the same state for two different values ofn?/olov-- Supplicant: I don't know if I'm alive or dead.Oracle: So much for Descartes. -- Internet Oracularity #1151-05 === > The important thing to know is how many ahead (or behind) the 1s are> on the 0s. At every stage of reading a string, this is some number> n. Can the machine be in the same state for two different values of> n?> /olovApparently not since each value of n requires a seperate state.However, I can't entirely convince myself of this. I think theargument that surges is that the number of states changes fordifferent values of n. Am I thinking in the right direction?Bernd === > >>The important thing to know is how many ahead (or behind) the 1s are>>on the 0s. At every stage of reading a string, this is some number>>n. Can the machine be in the same state for two different values of>>n?>>/olov> Apparently not since each value of n requires a seperate state.> However, I can't entirely convince myself of this. I think the> argument that surges is that the number of states changes for> different values of n. Am I thinking in the right direction?> > BerndThis post is relatively old, so nobody may still be interested in it. You are indeed thinking in the right direction. The problem can be proved using the Pumping Lemma for regular languages. A google search is fruitful, especially since the ?st entry (for me) was a delightful poem-turned-lemma!Robert === > ...> The gist of it is that I have a *proof* that an algebraic integer> which I called x in the original post has another algebraic integer> factor that I called y, but x/y is NOT an algebraic integer.> That's it. That's the contradiction which I say proves that the ring> of algebraic integers is incomplete as x/y should be included.> > ...> Why? Why if x and y are in a ring, should x/y be in it as well? > Consider the ring of rational integers.> GC> In a special case, I prove that a number I'll call x has a factor I'll> here call y, where both are in the ring of algebraic integers.> Given that y is a factor x, by de?ition x/y is in the ring of> algebraic integers, but in the special case it provably is not.> That's the contradiction.It's been hard to explain.Later I realized that y can't be a factor of x in the ring ofalgebraic integers, so I'd been going to a higher ring, like talkingof 2 and 6 being coprime in the ring of evens, and then saying that 2is a factor of 6, which it is, but in the ring of integers.Thinking about it this afternoon it seems to me that the gist of theargument is that given xyz=w, where w is an integer, you can ?d x, yand z, algebraic integers, such that neither xy, xz, nor yz, is analgebraic integer.More speci?ally considering the expressions I've often used, youhave a_1 a_2 a_3 = 65where neither a_1 a_2, a_2 a_3, nor a_1 a_3 is an algebraic integer.The a's here given by, from the expression used in my paper AdvancedPolynomial Factorization: a^3 + 12a^2 - 65 = 0.Given that you have the product of two algebraic integers NOT being analgebraic integer, the ring is incomplete.Note: Any proof that a_1 a_2, a_2 a_3, or a_1 a_3 is an algebraicinteger would de?itely cause me problems. And I'm not sayingproof but a proof, which means that the mathematical argument istrue, not just that there's some yahoo claiming they have a proof,when actually they just have a ?argument.James Harris === > Thinking about it this afternoon it seems to me that the gist of the> argument is that given xyz=w, where w is an integer, you can ?d x, y> and z, algebraic integers, such that neither xy, xz, nor yz, is an> algebraic integer.You may want to check http://www.jmilne.org/math/CourseNotes/math594f.pdfJ.S.Milne, Fields and Galois Theory, Page 9, Lemma 1.15: The algebraic integers form a subring of the complex numbers. === [.snip.]>Thinking about it this afternoon it seems to me that the gist of the>argument is that given xyz=w, where w is an integer, you can ?d x, y>and z, algebraic integers, such that neither xy, xz, nor yz, is an>algebraic integer.In short, you are saying that the algebraic integers do not form aring, as they are not closed under multiplication.That will come as a great surprise to Eisenstein, Gauss's favoritepupil, who proved that if x and y are algebraic integers, then so arex+y and x*y...>Note: Any proof that a_1 a_2, a_2 a_3, or a_1 a_3 is an algebraic>integer would de?itely cause me problems. And I'm not saying>proof but a proof, which means that the mathematical argument is>true, not just that there's some yahoo claiming they have a proof,>when actually they just have a ?argument.Amazing. You have just described perfectly most of your arguments(that's some yahoo claiming they have a proof, when actually theyjust have a ?argument).Recall: a complex number c is an ALGEBRAIC INTEGER if and only ifthere exists a monic polynomial f(x) with integer coef?ients suchthat f(c)=0.Recall also that by subring of C we mean a nonempty set R of complexnumbers with the following properties:(i) 0 is in R.(ii) 1 is in R.(iii) If a and b are in R, then a-b is in R (usual complex subtraction).(iv) If a and b are in R, then a*b is in R (usual complex multiplication).Finally, let R be a subring of C. We say that the additive group of Ris ?itely generated to mean that there exist a ?ite number ofelements of R, a_1,...,a_m, such that every element of R may bewritten in at least one way asc_1*a_1 + ... + c_m*a_m, where c_1,...,c_m are (rational) integers.THEOREM. The following are equivalent for a complex number a (that is,if one of them is true, then they are all true; if one of them isfalse, then they are all false): (i) a is an algebraic integer. (ii) The additive group of the ring Z[a] (the smallest ring contained in the complex numbers which contains all integers and contains a; it consists of all polynomial expressions in a with coef?ients in Z) is ?itely generated.(iii) a is a member of some subring of the complex numbers whose additive group is ?itely generated. (iv) There exists a ?itely generated additive subgroup of C, called A, with the property that aA is contained in A.Proof. To prove the equivalence, we show that if (i) holds, then (ii)holds; that if (ii) holds, then (iii) holds; that if (iii) holds, then(iv) holds; and that if (iv) holds, then (i) holds. That is, we provethat (i)->(ii)->(iii)->(iv)->(i).(i)->(ii) Assume that a is an algebraic integer. Then thereexists a monic polynomial with integer coef?ients, f(x), such thatf(a)=0; letf(x) = x^n + a_{n-1}*x^{n-1} + ... + a_1*x + a_0,with a_i an integer. By substituting a^n = -(a_{n-1}*a^{n-1} + ... + a_1*a + a_0) into anyexpression of the formb_m*a^m + ... b_1*a + b_0, with b_i integers, we see that everyelement of Z[a] may be written as a polynomial expression in a ofdegree strictly less than n and integer coef?ients. That is,Z[a] = {c_{n-1}*a^{n-1} + ... + c_1*a + c_0 : c_i integers}.As a group, Z[a] is generated by 1, a, a^2, ... , a^{n-1}. Therefore,Z[a] is ?itely generated, proving (ii).(ii) -> (iii). Assume that Z[a] has ?itely generated additivegroup. Then Z[a] is a subring of C which contains a, and with theproperty that its additive group is ?itely generated. Thus, if (ii)holds, then (iii) must hold as well.(iii)->(iv) Assume there is a subring R of the complex numbers, withthe properties that a is in R, and the additive group of R is ?itelygenerated. Since R is a ring, the product of any two elements of R must be inR. Therefore, aR = {a*r : r in R} is a subset of R (since both a and rare in R); thus, A=R shows that (iv) is true.Finally, we prove that if (iv) holds, then (i) holds.Assume that (iv) holds. Let A be a ?itely generated additivesubgroup of C such that a*A is contained in A. Let x_1,...,x_m beelements of A such that every element of A may be written asc_1*x_1 + ... + c_m*x_m, with c_1,...,c_m integers.Furthermore, we may assume that none of the x_i are equal to 0.Our assumption is that for every choice of integers c_1,...,c_m,(c_1*x_1 + ... + c_m*x_m)*a is in A.For each i, a*x_i lies in A; therefore, a*x_i may be written asabove. We write:a*x_1 = b_{11}*x_1 + b_{21}*x_2 + ... + b_{m1}*x_ma*x_2 = b_{12}*x_1 + b_{22}*x_2 + ... + b_{m2}*x_m . . .a*x_m = b_{1m}*x_1 + b_{2m}*x_2 + ... + b_{mm}*x_m.Let M be the matrix ( b_{11} b_{21} ... b_{m1} ) ( b_{12} b_{22} ... b_{m2} ) ( . . . . ) M= ( . . . . ) ( . . . . ) ( b_{1m} b_{2m} ... b_{mm} )this is an m x m matrix with integer coef?ients, such that (x_1) (x_1) (x_2) (x_2) ( . ) ( . )a*( . ) = M( . ) ( . ) ( . ) (x_m) (x_m)If I is the m x m identity matrix, this means that (x_1) (x_2) ( . )(a*I - M)( . ) ( . ) (x_m)is the zero vector. Since none of the x_i are equal to 0, it followsthat a is an eigenvalue of M and the vector of the x_i is aneigenvector of M. That means that det(aI-M) = 0. Equivalently, thecharacteristic polynomial of M, det(xI-M), has a as a root. Since Mhas integer coef?ients, the characteristic polynomial of M is monicand has integer coef?ients. Therefore, a is the root of a monicpolynomial with integer coef?ients. Therefore, a is an algebraicinteger, proving that (i) holds whenever (iv) holds. QEDCorollary. Let a and b be algebraic integers. Then a+b, a-b, and a*bare all algebraic integers.Proof. Consider the ring Z[a,b], the smallest subring of C whichcontains a, b, and all the integers. Note that it contains a+b, a-b,and a*b, by de?ition of subring.By clause (iii) of the Theorem, in order to prove that a+b, a-b, anda*b are algebraic integers it is enough to prove that Z[a,b] has?itely generated additive group.Since a is an algebraic integer, we know that a satis?s a monicpolynomial with integer coef?ients, say:f(x) = x^n + a_{n-1}*x^{n-1} + ... + a_1*x + a_0;likewise, b satis?s a monic polynomial with integer coef?ients,say:g(x) = x^m + b_{m-1}*x^{m-1} + ... + b_1*x + b_0.CLAIM: Z[a,b] is generated, as an additive group, by1, a, a^2, ..., a^{n-1}, b, ba, ba^2, ..., ba^{n-1}, b^2,....,b^{m-1}a^{n-1}.Note that establishing the claim will prove the corollary.Every element of Z[a,b] may be written as a polynomial expression in aand b with integer coef?ients. Sincea^n = -(a_{n-1}*a^{n-1} + ... + a_1*a + a_0)b^m = -(b_{m-1}*b^{m-1} + ... + b_1*b + b_0),we may substitute any occurance of any power of a greater thana^{n-1}, and any power of b greater than b^{m-1}, by an expressioninvolving only lesser powers. Therefore, by repeating thesubstitution, we may write every element of Z[a,b] as:c_{n-1,m-1}*a^{n-1}*b^{m-1} + c_{n-1,m-2}*a^{n-1}*b^{m-2} + ... + + c_{n-1,0}*a^{n-1} + c_{n-2,m-1}*a^{n-2}b^{m-1} + ... + a_{0,0}*1.This proves the claim. This proves the Corollary. QEDThis proves that if a and b are algebraic integers, then so is a*b.This de?itely cause[s you] problems. === ==================================== === ============Why do you take so much trouble to expose such a reasoner as Mr. Smith? I answer as a deceased friend of mine used to answer on like occasions - A man's capacity is no measure of his power to do mischief. Mr. Smith has untiring energy, which does something; self-evident honesty of conviction, which does more; and a long purse, which does most of all. He has made at least ten publications, full of ?ures few readers can critize. A great many people are staggered to this extend, that they imagine there must be the inde?ite something in the mysterious all this. They are brought to the point of suspicion that the mathematicians ought not to treat all this with such undisguised contempt, at least. -- A Budget of Paradoxes, Vol. 2 p. 129 by Augustus de Morgan === ======================================= === =========Arturo Magidinmagidin@math.berkeley.edu === [snip latest sideshow]> Note: Any proof that a_1 a_2, a_2 a_3, or a_1 a_3 is an algebraic> integer would de?itely cause me problems. And I'm not saying> proof but a proof, which means that the mathematical argument is> true, not just that there's some yahoo claiming they have a proof,> when actually they just have a ?argument.It's already been done by several posters (not yahoos). Wake up and smell the coffee you moron. You arehereby banned from the sandbox. Go climb back under the rock whence you came.--There are two things you must never attempt to prove: the unprovable -- and the obvious.--Democracy: The triumph of popularity over principle.--http://www.crbond.com === > ...> > The gist of it is that I have a *proof* that an algebraic integer> which I called x in the original post has another algebraic integer> factor that I called y, but x/y is NOT an algebraic integer.> That's it. That's the contradiction which I say proves that the ring> of algebraic integers is incomplete as x/y should be included.> ...> Why? Why if x and y are in a ring, should x/y be in it as well? > > Consider the ring of rational integers.> GC> > In a special case, I prove that a number I'll call x has a factor I'll> here call y, where both are in the ring of algebraic integers.> Given that y is a factor x, by de?ition x/y is in the ring of> algebraic integers, but in the special case it provably is not.> That's the contradiction.> > It's been hard to explain.> Later I realized that y can't be a factor of x in the ring of> algebraic integers, so I'd been going to a higher ring, like talking> of 2 and 6 being coprime in the ring of evens, and then saying that 2> is a factor of 6, which it is, but in the ring of integers.> Thinking about it this afternoon it seems to me that the gist of the> argument is that given xyz=w, where w is an integer, you can ?d x, y> and z, algebraic integers, such that neither xy, xz, nor yz, is an> algebraic integer.Nope. That's not it. > More speci?ally considering the expressions I've often used, you> have> a_1 a_2 a_3 = 65> where neither a_1 a_2, a_2 a_3, nor a_1 a_3 is an algebraic integer.They are as is easily shown.> The a's here given by, from the expression used in my paper Advanced> Polynomial Factorization:> a^3 + 12a^2 - 65 = 0.> Given that you have the product of two algebraic integers NOT being an> algebraic integer, the ring is incomplete.> Note: Any proof that a_1 a_2, a_2 a_3, or a_1 a_3 is an algebraic> integer would de?itely cause me problems. And I'm not saying> proof but a proof, which means that the mathematical argument is> true, not just that there's some yahoo claiming they have a proof,> when actually they just have a ?argument.Oh well, that was wrong.However, I ?d it interesting that my earlier post received some replies. James Harris === >> [...]>>It's been hard to explain.>>[...]>>Thinking about it this afternoon it seems to me that the gist of the>argument is that given xyz=w, where w is an integer, you can ?d x, y>and z, algebraic integers, such that neither xy, xz, nor yz, is an>algebraic integer.Yes, that _is_ hard to explain. Why? Because it's simply _false_. Easily shown to be false, alsowell-known to be false. When you say this is hard to explain it's_exactly_ like if you'd said you'd had a hard time explaining yourtheory, then you realized the gist of it was that 2 + 2 = 5.(Well, not exactly like that - the difference is that _you_ knowenough math to see that 2 + 2 = 5 is false. But to someonewho actually knows something about this stuff it's exactlythe same. You talk a lot about how we all lie about thesethings. When you do that the impression you make isexactly like someone complaining about people lying,saying that 2 + 2 = 4. Honest.)>More speci?ally considering the expressions I've often used, you>have>> a_1 a_2 a_3 = 65>>where neither a_1 a_2, a_2 a_3, nor a_1 a_3 is an algebraic integer.>>The a's here given by, from the expression used in my paper Advanced>Polynomial Factorization:>> a^3 + 12a^2 - 65 = 0.>>Given that you have the product of two algebraic integers NOT being an>algebraic integer, the ring is incomplete.>>Note: Any proof that a_1 a_2, a_2 a_3, or a_1 a_3 is an algebraic>integer would de?itely cause me problems. And I'm not saying>proof but a proof, which means that the mathematical argument is>true, not just that there's some yahoo claiming they have a proof,>when actually they just have a ?argument.>James Harris************************David C. Ullrich === with this informal admission,I hereby (again) declare my solemn intentionnot to participate in heckling monsieur Harris, any more, ifI can possibly help it. even if he can't help instigating it. of course, there could be an ulterior motive to all of this,as it's so hard to believe! > Note: Any proof that a_1 a_2, a_2 a_3, or a_1 a_3 is an algebraic> integer would de?itely cause me problems. And I'm not saying> proof but a proof, which means that the mathematical argument is> true, not just that there's some yahoo claiming they have a proof,> when actually they just have a ?argument.> Oh well, that was wrong.--UN HYDROGEN (sic; Methanex (TM) reformanteurs) ECONOMIE?...La Troi Phases d'Exploitation de la Protocols des Grises de Kyoto:(FOSSILISATION [McCainanites?] (TM/sic))/BORE/GUSH/NADIR @ http://www.tarpley.net/aobook.htm.Http://www.tarpley.net/ bushb.htm (content partiale, below): 17 -- L'ATTEMPTER de COUP D'ETAT, 3/30/81 === > And I'm not saying> proof but a proof, which means that the mathematical argument is> true, not just that there's some yahoo claiming they have a proof,> when actually they just have a ?argument.> James HarrisJSH has lots of experience in this area. === I was leading my class through related rates yesterday, and one of the students stunned me by asking for a good qualitative description of what a derivative means. (He asked it in a more basic form, which is why I was stunned.)Our textbook, Larson/Hostetler/Edwards, really doesn't do a very good job of explaining what a derivative _means_, now that I look at it with fresh eyes.I pointed him at /Calculus Made Easy/, which I think is pretty good at that. But is there a Web resource I can give to all my students? Once again, the issue is not how to ?d derivatives but how to understand them.-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/You ?d yourself amusing, Blackadder.I try not to ?the face of public opinion. === A derivative is the rate of change of a function. If you graph the functionthe derivative is the slope of the graph.A good example is that the derivative of position is velocity, thederivative of velocity is acceleration.>> I was leading my class through related rates yesterday, and one of> the students stunned me by asking for a good qualitative description> of what a derivative means. (He asked it in a more basic form, which> is why I was stunned.)>> Our textbook, Larson/Hostetler/Edwards, really doesn't do a very> good job of explaining what a derivative _means_, now that I look at> it with fresh eyes.>> I pointed him at /Calculus Made Easy/, which I think is pretty good> at that. But is there a Web resource I can give to all my students?>> Once again, the issue is not how to ?d derivatives but how to> understand them.>> -- > Stan Brown, Oak Road Systems, Cortland County, New York, USA> http://OakRoadSystems.com/> You ?d yourself amusing, Blackadder.> I try not to ?the face of public opinion. === > A derivative is the rate of change of a function. If you graph thefunction> the derivative is the slope of the graph.> A good example is that the derivative of position is velocity, the> derivative of velocity is acceleration.derivative is often interpreted as a rate of change. You mean well, weknow, and I may be wrong but I think what Stan has in mind is he is havingtrouble explaining, satisfactorilly, and at a certain intuitive/qualitativelevel, what a derivative _means_. Textbooks are good at giving veryunambiguous de?itions, but not so good many times at explaining thesethings at a more basic level.Although I don't have the most current edition of Larson, et al, I do havethe 5th ed. handy and if the one Stan has is anything like it, I understandexactly what he is talking about. In my edition, the way the authorsattempt to put a derivative in layman's terms, so to speak, is fairlyconfusing. They begin this attempt somewhere in ch. 1 with a sectionentitled the tangent line problem then they drop that discussion entirely,moving on to other things, and later in chapter 2 I believe, they pick backup with that discussion. At face value, this seems not that unreasonablesince the problem of ?ding a derivitive *is* essentially the same as?dling the slope of a tangent line (hence, the tangent line itself) but ifyou have had to experience reading the actual material, in the mannerpresented, you may agree that the authors were not very effective in thisattempt to explain a derivative. Yeah, they do a good job of explaing howthe secant line approaches the tangent line, etc, etc, and how the limitingposition of the secant line is the tangent line, etc. but this reallydoesn't address what a derivative _means_. It just addresses what one _is_.so why _are_ we interested in tangent lines? What do _they_ mean?All that said, it's not the easiest thing in the world to explain what aderivative _means_ as Stan has acknowledged (and Larson, et al.demonstrates). But here are a couple of places you may want to look, if youhaven't already:http://karlscalculus.org/calculus.htmlKarl goes into extreme vivid detailed explanations, in layman's terms,(borderline children's talk, in some places, if that kind of stuff doesn'tbother you or your students). All the rigor is there, but buried deepwithin lengthy, informal explanations in story format. It may be necessaryto start his story with the limit chapter.http://www.sosmath.com/calculus/diff/der00/der00. htmlThis is an excellent site that is much more concise than karl's, geared tomore of a grown up audience, if you will. They discuss both commoninterpretations, that of a physical rate of change and that of the(geometrical) slope of a tangent line. but they do a much better job at it,IMO, than larson, et. al.HTH,-- Darrell> I was leading my class through related rates yesterday, and one of> the students stunned me by asking for a good qualitative description> of what a derivative means. (He asked it in a more basic form, which> is why I was stunned.)>> Our textbook, Larson/Hostetler/Edwards, really doesn't do a very> good job of explaining what a derivative _means_, now that I look at> it with fresh eyes.>> I pointed him at /Calculus Made Easy/, which I think is pretty good> at that. But is there a Web resource I can give to all my students?>> Once again, the issue is not how to ?d derivatives but how to> understand them.>> -- > Stan Brown, Oak Road Systems, Cortland County, New York, USA> http://OakRoadSystems.com/> You ?d yourself amusing, Blackadder.> I try not to ?the face of public opinion.>> === >> A derivative is the rate of change of a function. If you graph the>function>> the derivative is the slope of the graph.>> A good example is that the derivative of position is velocity, the>> derivative of velocity is acceleration.>>derivative is often interpreted as a rate of change. You mean well, we>know, and I may be wrong but I think what Stan has in mind is he is having>trouble explaining, satisfactorilly, and at a certain intuitive/qualitative>level, what a derivative _means_. You interpret rightly. Since I'm teaching calculus, I should certainly hope I know what a derivative is! :-)>http://karlscalculus.org/calculus.html>Karl goes into extreme vivid detailed explanations, in layman's terms,>(borderline children's talk, in some places, if that kind of stuff doesn't>bother you or your students).Nope. When the student was explaining his dif?ulty, he said, Talk to me like I'm 4.>http://www.sosmath.com/calculus/diff/der00/der00.html> This is an excellent site that is much more concise than karl's, geared to>more of a grown up audience, if you will. Every time I look at sosmath I block it out mentally because I don't like the ad for calc101.com, which is essentially Pay us and we'll do your homework. But the page itself does look good.-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/You ?d yourself amusing, Blackadder.I try not to ?the face of public opinion. === I'm trying to derive the properties of determinants, as opposed to just provingthem. Hence I'm pretending ignorance of determinants, and trying to computeeigenvalues by primitive methods. In case that kind of thing doesn't interestyou, you've been warned. This is where I'm at:Suppose A is a square matrix and I is the identity matrix of the same order. LetX_0 be (A-xI), where x is a variable. Assuming X_0[1,1]<>0, there are rowoperations that convert X_0 into a matrix X_1 with X_1[1,j]=0 for j>1.Continuing in the same way you eventually obtain a matrix X_n that can beconverted into I provided none of the entries on its main diagonal is zero.Hence every eigenvalue of A is a root of numer(X_n[1,1])*...*numer(X_n[n,n]),where numer(r) means the polynomial p with r=p/q for p and q relatively prime.Now, it turns out that numer(X_n[n,n]) is the characteristic polynomial of A(recall that I don't of?ially know about the characteristic polynomial at thispoint), so that none of the numer(X_n[i,i])'s with i I'm trying to derive the properties of determinants, as opposed to just proving> them. Hence I'm pretending ignorance of determinants, and trying to compute> eigenvalues by primitive methods.I don't think computing eigenvalues is a property of determinants.So this might not be the best way to investigate determinants.I think of the properties of a determinant as being multilinear andskew symmetric.One approach at viewing determinants is to consider it as thevolume of the parallelpiped formed by the row vectors of the matrix.Another approach is to consider it as a differential n-form.A third approach is to see how determinants pop-up when tryingto solve n equations in n unknowns using Kramer's rule. I liketo use Kramer's rule in the form D * x_i = c_i since it istrue even when D is zero (here D is the determinant).> In case that kind of thing doesn't interest> you, you've been warned. This is where I'm at:> Suppose A is a square matrix and I is the identity matrix of the same order. Let> X_0 be (A-xI), where x is a variable. Assuming X_0[1,1]<>0, there are row> operations that convert X_0 into a matrix X_1 with X_1[1,j]=0 for j>1.> Continuing in the same way you eventually obtain a matrix X_n that can be> converted into I provided none of the entries on its main diagonal is zero.> Hence every eigenvalue of A is a root of numer(X_n[1,1])*...*numer(X_n[n,n]),> where numer(r) means the polynomial p with r=p/q for p and q relatively prime.> Now, it turns out that numer(X_n[n,n]) is the characteristic polynomial of A> (recall that I don't of?ially know about the characteristic polynomial at this> point), so that none of the numer(X_n[i,i])'s with i for a root.> Can anybody explain this fact without invoking a bunch of involved theory?Let A be the square matrix [a,b;c,d].Let u = (x,y) be an eigenvector with eigenvalue k.Then, A*u = k*u.Thus, a*x + b*y = k*x c*x + d*y = k*y.That is, (a-k)*x + b*y = 0 c*x + (d-k)*y = 0Note that (0,0) is not considered an eigenvector.Thus, either x or y is non-zero.I have two equations in two unknowns x and y, with paramenter k.Solve for the non-zero unknown, say x, using the method youlearned in high school.You get: (a-k)*(d-k)*x - b*c*x = 0.Since x is not zero, you get (a-k)*(d-k) - b*c = 0.This is just the determinant since the determinantpops up when you solve linear equations for the unknowns.This doesn't seem to be what you are looking for though.-- Bill Hale === > I'm trying to derive the properties of determinants, as opposed to just proving> them. Hence I'm pretending ignorance of determinants, and trying to compute> eigenvalues by primitive methods. In case that kind of thing doesn't interest> you, you've been warned. This is where I'm at:> Suppose A is a square matrix and I is the identity matrix of the same order. Let> X_0 be (A-xI), where x is a variable. Assuming X_0[1,1]<>0, there are row> operations that convert X_0 into a matrix X_1 with X_1[1,j]=0 for j>1.> Continuing in the same way you eventually obtain a matrix X_n that can be> converted into I provided none of the entries on its main diagonal is zero.> Hence every eigenvalue of A is a root of numer(X_n[1,1])*...*numer(X_n[n,n]),> where numer(r) means the polynomial p with r=p/q for p and q relatively prime.> Now, it turns out that numer(X_n[n,n]) is the characteristic polynomial of A> (recall that I don't of?ially know about the characteristic polynomial at this> point), so that none of the numer(X_n[i,i])'s with i for a root.> Can anybody explain this fact without invoking a bunch of involved theory?Have a look at the book Linear Algebra Done Right by Sheldon Axler,for a consistently determinant-free approach to basic linear algebra. The book's homepage is at:http://math.sfsu.edu/axler/LADR.htmlHTH,Felix.P.S: Note that Axler allows the zero vector to be an eigenvector,which is quite non-standard usage. Apart from that, the book is anexcellent presentation of classic material in an elegant way.P.P.S[Full Disclousre]: Personally, I think that determinants are justok. === >URGENT PLEASE READ>Our friend recently suffered a heart attack at 46 years old. >He is a regularly working contracted employee (self employed) who will be unable to work for 6 or 7 weeks from the time of the heart attack with absolutely no income.>He has paid taxes all of his life but is not eligible for government assistance>of any type as his wife is working earning $1400.00 monthly. This obviously does not support their family including their 2 kids but does exclude them from any agency help. >Mrs. Sheffer was even told that if she were a crack head or unemployed, they could then offer assistance.>They have now missed their rent, had to give up their car, had to add $300 monthly in medications and the quality of their life has sunken to new lows. >This is a kind and considerate hard working family who has fallen on temporary hard times and could sure use a kindly hand before it's too late.>We are trying to prove that people DO still care even if our government doesn't.>We have set up a donation PO Box at the address below and could sure use your help!>>Donna Sheffer, 3216 Eglinton ave. east, Scarborough, Ontario, Canada, M1J 2H6>Your generous donation $1, $2, $5, $10, $20 whatever would be greatly appreciated.>Help restore a little faith and save a real family.>God Bless>See the angioplasty image here. http://www.otwebdesign.com/apimage.jpg>>This is no scam>Please help!! I faxed you a $100 bill ! Do you really think we're all idiots? === [snip by Stan]>>This is no scam>>Please help!!> I faxed you a $100 bill !>> Do you really think we're all idiots?Some of we apparently are. You found it necessary to repost the whole scam, including the Web site and the postal address, thus giving the spammer another shot at our eyes.-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/You ?d yourself amusing, Blackadder.I try not to ?the face of public opinion. === >> [snip by Stan]>>This is no scam> >>Please help!!> I faxed you a $100 bill !>> Do you really think we're all idiots?>> Some of we apparently are. You found it necessary to repost the> whole scam, including the Web site and the postal address, thus> giving the spammer another shot at our eyes.However, the tragedy may be real, and the arrogantreplies thus all the more hurtful. But we cannotknow for sure: hence paranoia prevails...Christian--In the paranoid-schizoid position ... there is no concernfor the consequences of actions, and certainly not for theireffects on others. At most there is the operation of a talionmorality, a cold exchange of goods and evils.- Eugene Victor Wolfenstein: ?Psychoanalytic-Marxism, Groundwork' === I need help with proving the following statement: When the vertex of an angle is in the exterior of a circle, the measureof the angle is one-half the difference of the measures of the interceptedarcs.Any hints or directions to look in would be appreciated. === >I need help with proving the following statement:>> When the vertex of an angle is in the exterior of a circle, the measure>of the angle is one-half the difference of the measures of the intercepted>arcs.>>Any hints or directions to look in would be appreciated.Are we to assume that the sides of the angle are tangent to the circle?If so, try drawing radii to the two points of tangency. You will then have two right angles; you will also have an interior angle of the circle (which has a simple relationship to both arc lengths). If you draw the diagonal of the quadrilateral from the center of the circle to the vertex of the external angle, you will have two congruent right triangles.I think if you try that and do some playing around you should see a method of attack. But I should disclose that I haven't completed the proof myself, so I'm telling you how I _would_ start and not how I _did_ start.-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/Walrus meat as a diet is less repulsive than seal. === > When the vertex of an angle is in the exterior of a circle, the measure> of the angle is one-half the difference of the measures of the intercepted> arcs.>> Any hints or directions to look in would be appreciated.>What happens if the angle's line miss the circle or just one passes thruor touches the circle? === In a particular retail store the average price of a typical two-seater sofahas been 200 and average sales were 1000 per year. This year the store hasrun a half price sale on such sofas and found that sales increased by 50%.Question: Find a hyperbolic model for demand in terms of price. === Suppose that in a triangle ABC a,b,c are the sides ,2s=a+b+c , r= radius of incircle , R= radius of circumcircle.Denote D= sqrt{s^2-3r(4R+r)} .Prove that(1) D =< max{a,b,c} - min{a,b,c} =< 2D/sqrt{3} .If a =< b =< c , prove or disprove the inequalities: (2) min{b-a,c-b} =< D/sqrt{3} ,(3) D =< 2c-(a+b) =< 2D , |2b-(a+c)| =< D , D=< (b+c)-2a =< 2D . === =To: geometry-college@moderators.isc.org===Suppose that in a triangle ABC a,b,c are the sides , r= radius of incircle , R= radius of circumcircle.Denote D= sqrt{s^2-3r(4R+r)} .Prove that(1) D =< max{a,b,c} - min{a,b,c} =< 2D/sqrt{3} .If a =< b =< c , prove or disprove the inequalities: (2) min{b-a,c-b} =< D/sqrt{3} ,(3) D =< 2c-(a+b) =< 2D , |2b-(a+c)| =< D , D=< (b+c)-2a =< 2D . === ====Let G be an in?ite abelian group such that every proper subgroup ofG is ?ite. Show that G is isomorphic to Z(p^infty), whereZ(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }I've been looking at this one for a week and nothing. Can somebodyhelp! It's driving me crazy. === >Let G be an in?ite abelian group such that every proper subgroup of>G is ?ite. Show that G is isomorphic to Z(p^infty), where>>Z(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }>>I've been looking at this one for a week and nothing. Can somebody>help! It's driving me crazy.You say you have gotten nothing, so some comments, which may helpgetting you started; I haven't thought it through in detail, so Icould be wrong in some things. But it seems right to me:First, note that G is a torsion group; as such, it can be decomposedinto a direct sum of its p-parts, that isG = G_2 oplus G_3 oplus G_5 oplus ...where G_p = {g in G; g^{p^m}=e for some m>0}.Now, let's consider only the non-trivial p-parts; so we haveG = G_{p_1} oplus G_{p_2} oplus ...Note that there cannot be an in?ite number of non-trivial p-parts;if there were, then the subgroup G_{p_2}oplus ... would be a properin?ite subgroup. SoG= G_{p_1} oplus G_{p_2} oplus ... oplus G_{p_m};since G is in?ite, at least one of the G_{p_i} is in?ite. Butthen, G_{p_i} itself is an in?ite subgroup of G, nontrivial. HenceG=G_{p_i}. That is, G is an in?ite p-group.Now consider the quotients G/pG, pG/p^2G, p^2G/p^3G,...these quotients are vector spaces over F_p, hence they have awell-de?ed dimension. Prove that the dimensions are non-increasing,able to conclude (a) that there exists m>0 such that p^mG/p^{m+1}/G iscyclic; and then that (b) all of them are cyclic; using the fact thatG does not have in?ite proper subgroups.Once you have that all of them are cyclic, it should not be hard towrite down an isomorphism. === ================================== === =============It's not denial. I'm just very selective about what I accept as reality. --- Calvin (Calvin and Hobbes) === ===================================== === ==========Arturo Magidinmagidin@math.berkeley.edu === Hmmm...I think I follow you, but I still don't see the actual isomorphism...>Let G be an in?ite abelian group such that every proper subgroup of>G is ?ite. Show that G is isomorphic to Z(p^infty), where>>Z(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }> >>I've been looking at this one for a week and nothing. Can somebody>help! It's driving me crazy.> You say you have gotten nothing, so some comments, which may help> getting you started; I haven't thought it through in detail, so I> could be wrong in some things. But it seems right to me:> First, note that G is a torsion group; as such, it can be decomposed> into a direct sum of its p-parts, that is> G = G_2 oplus G_3 oplus G_5 oplus ...> where G_p = {g in G; g^{p^m}=e for some m>0}.> Now, let's consider only the non-trivial p-parts; so we have> G = G_{p_1} oplus G_{p_2} oplus ...> Note that there cannot be an in?ite number of non-trivial p-parts;> if there were, then the subgroup G_{p_2}oplus ... would be a proper> in?ite subgroup. So> G= G_{p_1} oplus G_{p_2} oplus ... oplus G_{p_m};> since G is in?ite, at least one of the G_{p_i} is in?ite. But> then, G_{p_i} itself is an in?ite subgroup of G, nontrivial. Hence> G=G_{p_i}. That is, G is an in?ite p-group.> Now consider the quotients G/pG, pG/p^2G, p^2G/p^3G,...> these quotients are vector spaces over F_p, hence they have a> well-de?ed dimension. Prove that the dimensions are non-increasing,> able to conclude (a) that there exists m>0 such that p^mG/p^{m+1}/G is> cyclic; and then that (b) all of them are cyclic; using the fact that> G does not have in?ite proper subgroups.> Once you have that all of them are cyclic, it should not be hard to> write down an isomorphism.> === =========================================== === ====> It's not denial. I'm just very selective about> what I accept as reality.> --- Calvin (Calvin and Hobbes)> === ============================================ === ===> Arturo Magidin> magidin@math.berkeley.edu===> Let G be an in?ite abelian group such that every proper subgroup of> G is ?ite. Show that G is isomorphic to Z(p^infty), where> Z(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }> I've been looking at this one for a week and nothing. Can somebody> help! It's driving me crazy.This may involve some machinery that you don't have available. You can easily see that G must be a p-group. There is a theorem[Kulikov] that says G has a direct summand of the form Z_(p^n), 1 <= n <= oo. That summand can't be ?ite or else its complementarysummand would also be ?ite and hence G would be ?ite. So, thesummand is Z_(p^oo). The complementary summand must be 0 or else G hasan in?ite proper subgroup. Hence G is (isomorphic to) Z_(p^oo).-- Paul SperryColumbia, SC (USA) === > Let G be an in?ite abelian group such that every proper subgroup of> G is ?ite. Show that G is isomorphic to Z(p^infty), where> Z(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }But is every proper subgroup of this ?ite?Perhaps the question was: every proper subgroup of ?ite index?-- Timothy Murphy tel: +353-86-233 6090 === >>Let G be an in?ite abelian group such that every proper subgroup of>>G is ?ite. Show that G is isomorphic to Z(p^infty), where>> >Z(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }>>I've been looking at this one for a week and nothing. Can somebody>>help! It's driving me crazy.> You say you have gotten nothing, so some comments, which may help>> getting you started; I haven't thought it through in detail, so I>> could be wrong in some things. But it seems right to me:> First, note that G is a torsion group; as such, it can be decomposed>> into a direct sum of its p-parts, that is> G = G_2 oplus G_3 oplus G_5 oplus ...> where G_p = {g in G; g^{p^m}=e for some m>0}.> Now, let's consider only the non-trivial p-parts; so we have> G = G_{p_1} oplus G_{p_2} oplus ...> Note that there cannot be an in?ite number of non-trivial p-parts;>> if there were, then the subgroup G_{p_2}oplus ... would be a proper>> in?ite subgroup. So> G= G_{p_1} oplus G_{p_2} oplus ... oplus G_{p_m};> since G is in?ite, at least one of the G_{p_i} is in?ite. But>> then, G_{p_i} itself is an in?ite subgroup of G, nontrivial. Hence>> G=G_{p_i}. That is, G is an in?ite p-group.> Now consider the quotients G/pG, pG/p^2G, p^2G/p^3G,...>> these quotients are vector spaces over F_p, hence they have a>> well-de?ed dimension. Prove that the dimensions are non-increasing,>> able to conclude (a) that there exists m>0 such that p^mG/p^{m+1}/G is>> cyclic; and then that (b) all of them are cyclic; using the fact that>> G does not have in?ite proper subgroups.>> >> Once you have that all of them are cyclic, it should not be hard to>> write down an isomorphism.>Hmmm...I think I follow you, but I still don't see the actual isomorphism...Well, assuming everything I said was correct, and you have shown thatG is a p-group, and moreover, that each of p^iG/p^{i+1}G is cyclic,what does that mean? Can you show that G/p^iG is cyclic for all i>0?Now, take G/pG. This is cyclic of order p, say with generatorx+pG. Since G/p^2G is also cyclic, you should be able to see that itis generated by an element which, when multiplied by p, is equal tox. Call it x/p. Then you need to ?d one which when multiplied by pis x/p; call it x/p^2. Etc. === ======================================== === =======It's not denial. I'm just very selective about what I accept as reality. --- Calvin (Calvin and Hobbes) === ===================================== === ==========Arturo Magidinmagidin@math.berkeley.edu === >Let G be an in?ite abelian group such that every proper subgroup of>>G is ?ite. Show that G is isomorphic to Z(p^infty), where>> >Z(p^infty) = { [m/p^n] in Q/Z | m in Z, n in N }>>I've been looking at this one for a week and nothing. Can somebody>>help! It's driving me crazy.> You say you have gotten nothing, so some comments, which may help>> getting you started; I haven't thought it through in detail, so I>> could be wrong in some things. But it seems right to me:> First, note that G is a torsion group; as such, it can be decomposed>> into a direct sum of its p-parts, that is> G = G_2 oplus G_3 oplus G_5 oplus ...> where G_p = {g in G; g^{p^m}=e for some m>0}.> Now, let's consider only the non-trivial p-parts; so we have> G = G_{p_1} oplus G_{p_2} oplus ...> Note that there cannot be an in?ite number of non-trivial p-parts;>> if there were, then the subgroup G_{p_2}oplus ... would be a proper>> in?ite subgroup. So> G= G_{p_1} oplus G_{p_2} oplus ... oplus G_{p_m};> since G is in?ite, at least one of the G_{p_i} is in?ite. But>> then, G_{p_i} itself is an in?ite subgroup of G, nontrivial. Hence>> G=G_{p_i}. That is, G is an in?ite p-group.> Now consider the quotients G/pG, pG/p^2G, p^2G/p^3G,...>> these quotients are vector spaces over F_p, hence they have a>> well-de?ed dimension. Prove that the dimensions are non-increasing,>> able to conclude (a) that there exists m>0 such that p^mG/p^{m+1}/G is>> cyclic; and then that (b) all of them are cyclic; using the fact that>> G does not have in?ite proper subgroups.>> >> Once you have that all of them are cyclic, it should not be hard to>> write down an isomorphism.>Hmmm...I think I follow you, but I still don't see the actual isomorphism...Probably because the ?al two paragraphs are complete bollocks... Allthe quotients given will be trivial.I screwed up; I used the p-powers subgroups instead of the subgroupsof elements of exponent the p-powers...Here's a better way to proceed; we know that G is an in?itegroup. First, consider, pG. If pG were trivial, then G would be ofexponent p, hence an in?ite dimensional vector space over F_p, whichclearly has in?ite proper subgroups; so pG is nontrivial. If pGis ?ite, then G/pG is an in?ite dimensional vector space over F_p,and you can lift an in?ite proper subgroup to G. So pG is in?ite,hence pG=G. So G is divisible (being a p-group and p-divisible).At this point you could invoke classi?ation theorems for divisible abeliangroups, which will tell you that G must be a bunch of copies ofZ_p^{infty}, and thereby conclude that it must be equal to one ofthem. But here's a way to proceed without invoking thoseclassi?ation theorems:For each n>0, let G[p^n] = {g in G : g^{p^n}=e}, the subgroup ofelements of epxonent p^n. G[p] is nontrivial; let x in G[p] be different from e1. Since G isp-divisible, there is an element x_2 such that px_2 = x; an elementx_3 such that px_3=x_2; ...; an element x_{n+1} such that px_{n+1} =x_n.Let H = < x, x_2, x_3,...>It is now easy to verify that H is nontrivial and in?ite, so H=G. Itis now also easy to given an isomorphism from Z_{p^{infty}} to G: sent1/p + Q/Z to x, and 1/p^n +Q/Z to x_n, n>1. === ======================================== === =======It's not denial. I'm just very selective about what I accept as reality. --- Calvin (Calvin and Hobbes) === ===================================== === ==========Arturo Magidinmagidin@math.berkeley.edu === Can someone explain why the set of all integers is not a ?ld? === > Can someone explain why the set of all integers is not a ?ld?>What's the multiplicative inverse of 2? Is it an integer? === >Can someone explain why the set of all integers is not a ?ld?A ?ld is a set F with two binary operations, usually denoted + and *(sum and multiplication, respectively). The fact that they arebinary operations means they are functions from FxF to F (pairs ofelements to elements). However, it is usual in most places to usein? notation, and write x+y instead of +(x,y).The set F, together with the two operations + and *, must satisfycertain properties before it is called a ?ld:F must be an abelian group under the operation +. That means:(1) + must be associative: for all x,y,z in F, (x+y)+z = x+ (y+z).(2) There exists an element 0 in F such that for all x in F, x+0 = 0+x = x.(3) For every x in F there exists y in F such that x+y = y+x = 0. y is called the inverse of x and is often denoted -x; in that case, x-y means x+(-y).(4) + is commutative: for all x,y in F, x+y = y+x.In addition to these properties, F must be a commutative ring underthe operations + and *. That means:(5) * must be associative: for all x,y,z in F, (x*y)*z = z*(y*z).(6) * must distribute over +: for all x,y,z in F, x*(y+z) = (x*y) + (x*z) (y+z)*x = (y*x) + (z*x).(7) * must be commutative: for all x,y, in F, x*y = y*x.In addition to these properties, F must have a one:(8) There exists an element 1 in F such that for all x in F, 1*x = x*1 = x.And ?ally, in order to be a ?ld, every nonzero element of F musthave a multiplicative inverse:(9) For every x in F, if x is not equal to 0 (the same 0 in property (2) above), then there exists y in F such that x*y = y*x = 1.Now, are the integers a ?ld? First you must specify which twooperations you are considering. If you are using the usual additionand multiplication, then the answer is no because the integers failproperty (9): for example, if x=2, then x is not equal to 0, but theredoes not exist any integer y such that 2*y = 1. === ========================================== === ======It's not denial. I'm just very selective about what I accept as reality. --- Calvin (Calvin and Hobbes) === ===================================== === ==========Arturo Magidinmagidin@math.berkeley.edu === alt.math.undergrad, Cieslak Family Can someone explain why the set of all integers is not a ?ld?http://mathworld.wolfram.com/FieldAxioms.htmlCan you see which ?ld axiom is _not_ satis?d by the integers?(spoiler below)What is the multiplicative inverse of 6? Is it a member of the integers?-- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://OakRoadSystems.com/Walrus meat as a diet is less repulsive than seal. === > Can someone explain why the set of all integers is not a ?ld?>> === > >Can someone explain why the set of all integers is not a ?ld?>> A ?ld is a set F with two binary operations, usually denoted + and *> (sum and multiplication, respectively). The fact that they are> binary operations means they are functions from FxF to F (pairs of> elements to elements). However, it is usual in most places to use> in? notation, and write x+y instead of +(x,y).>> The set F, together with the two operations + and *, must satisfy> certain properties before it is called a ?ld:>> F must be an abelian group under the operation +. That means:>> (1) + must be associative: for all x,y,z in F,> (x+y)+z = x+ (y+z).> (2) There exists an element 0 in F such that for all x in F,> x+0 = 0+x = x.> (3) For every x in F there exists y in F such that x+y = y+x = 0. y is> called the inverse of x and is often denoted -x; in that> case, x-y means x+(-y).> (4) + is commutative: for all x,y in F,> x+y = y+x.>> In addition to these properties, F must be a commutative ring under> the operations + and *. That means:>> (5) * must be associative: for all x,y,z in F,> (x*y)*z = z*(y*z).>> (6) * must distribute over +: for all x,y,z in F,>> x*(y+z) = (x*y) + (x*z)> (y+z)*x = (y*x) + (z*x).>> (7) * must be commutative: for all x,y, in F,>> x*y = y*x.>> In addition to these properties, F must have a one:>> (8) There exists an element 1 in F such that for all x in F,>> 1*x = x*1 = x.>> And ?ally, in order to be a ?ld, every nonzero element of F must> have a multiplicative inverse:>> (9) For every x in F, if x is not equal to 0 (the same 0 in property> (2) above), then there exists y in F such that>> x*y = y*x = 1.> Now, are the integers a ?ld? First you must specify which two> operations you are considering. If you are using the usual addition> and multiplication, then the answer is no because the integers fail> property (9): for example, if x=2, then x is not equal to 0, but there> does not exist any integer y such that 2*y = 1.>> === =========================================== === ====> It's not denial. I'm just very selective about> what I accept as reality.> --- Calvin (Calvin and Hobbes)> === ============================================ === ===>> Arturo Magidin> magidin@math.berkeley.edu>===I am currently learning to do integration by parts. I'm havingdif?ulty on one problem, for which I get an answer that seems to beright to me, but which disagrees with the answer in the book. I'velooked for the errata for the book, but can't ?d it. Since I can'tdo the integral sign, I've made an image which can be found athttp://www.geocities.com/venture_free/Integration.jpg which displaysmy problem. I'll wait here while you go look at it.Now, the answer I keep coming up with is:xln2x - 1/2x - ln2 +1/2The answer in the back of the book, however, is:xln2x - x - ln2 + 1I think that I am assuming something different than the book is, and Idon't know if I'm wrong, or the book is. Basically, all else beingequal, I get my answer if:d/dt ln2t = 1/2tand I get the books answer if:d/dt ln2t = 1/t. Which of us is right, and why?Also, since I have your attention, is there some easier way to ?dbook errata than by just looking on Google?----------------------------- === [...]> I get my answer if:> d/dt ln2t = 1/2t> and I get the books answer if:> d/dt ln2t = 1/t. > Which of us is right, and why?Sorry, your book is right: d/dt(ln(2t)) = 1/(2t)*d/dt(2t) = 2/(2t) = 1/t.Or: ln(2t) = ln(2) + ln(t) so d/dt(ln(2t)) = d/dt(ln(t) = 1/t.For future reference, your problem was int(ln(2t), t=1..x).> Also, since I have your attention, is there some easier way to ?d> book errata than by just looking on Google?It never would have occurred to me to look _there_.-- Paul SperryColumbia, SC (USA) === > I am currently learning to do integration by parts. I'm having> dif?ulty on one problem, for which I get an answer that seems to be> right to me, but which disagrees with the answer in the book. I've> looked for the errata for the book, but can't ?d it. Since I can't> do the integral sign, I've made an image which can be found at> http://www.geocities.com/venture_free/Integration.jpg which displays> my problem. I'll wait here while you go look at it.Bah, boo.> Now, the answer I keep coming up with is:> xln2x - 1/2x - ln2 +1/2integeral log x dx = x log x - x> The answer in the back of the book, however, is:> xln2x - x - ln2 + 1>> I get my answer if:> d/dt ln2t = 1/2t>d/dt log 2t = 1/2t * 2 = 1/t> and I get the books answer if:> d/dt ln2t = 1/t.> Which of us is right, and why?>The book, because you made a mistake.> Also, since I have your attention, is there some easier way to ?d> book errata than by just looking on Google?>Go googling by title, publisher and/or author. === I'm trying to do a Fourier Series, but it's been too long since I tookCalculus. I'm starting with:Integral [limits 0 to pi] x*sin(nx)dxIntegrating by parts:u = x du = dxdv = sin(nx)dxv = -cos(nx) Integral x*sin(nx)dx = -x*cos(nx) - [integral] (-1)cos(nx)dx = -x*cos(nx) + [integral] cos(nx)dx === > I'm trying to do a Fourier Series, but it's been too long since I took> Calculus. > I'm starting with:> Integral [limits 0 to pi] x*sin(nx)dx> Integrating by parts:> u = x > du = dx> dv = sin(nx)dx> v = -cos(nx) > Integral x*sin(nx)dx = -x*cos(nx) - [integral] (-1)cos(nx)dx> = -x*cos(nx) + [integral] cos(nx)dx> constant (n). Odd, since you presumably (incorrectly) integrated sin(nx) to get v.In both cases substitute for nx.-- Paul SperryColumbia, SC (USA) === >I'm trying to do a Fourier Series, but it's been too long since I took>Calculus. >>I'm starting with:>>Integral [limits 0 to pi] x*sin(nx)dx>>Integrating by parts:>>u = x >du = dx>dv = sin(nx)dx>v = -cos(nx) >>Integral x*sin(nx)dx = -x*cos(nx) - [integral] (-1)cos(nx)dx> = -x*cos(nx) + [integral] cos(nx)dx>>constant (n). Is this part going to be equal to sin(nx) or something>else?> DUH! THINK! what's the derivative of sin(nx) ???? === I am trying to model two different savings plans here in the US, andseem to be running into contradictory results.There are two plans, an unmatched plan and a matched plan.You can add money to the unmatched plan like so:2004: 16k2005: 18k (it remains at 18k from here on)Then there is a matched plan (the employer adds 4k)2004: 20k2005: 22k (it remains at 22k from here on)When you withdraw your money, the unmatched plan is taxed at 15%,while the matched plan is taxed at 35% (this tax is only applied once,when withdrawing all the money). Assume 10% interest compoundedanually.It initially appears that after several years, the extra 4k added overand over again will make the matched plan more attractive. Apparentlythe latest BusinessWeek mentioned something to this effect.me contradictory results.Approaching the problem mathematically, I solved for U_n and M_n (forn > 2)U_n = unmatched funds after n yearsM_n = matched funds after n yearsI determined the formulas to be:U_n = 14000 * (1.1)^n + 16000 * (1.1)^(n-1) + 18000* (1.1^(n-1) -1.1)/(.1)M_n = 18000 * (1.1)^n + 20000 * (1.1)^(n-1) + 22000* (1.1^(n-1) -1.1)/(.1)The last terms of each equation are a simpli?d geometric seriesI want n, such that .85 * U_n = .65 * M_n. How do I solve for n?If you see any obvious problems with my program, feel free to pointthem out.If the funds never equal each other (which is what my program hintsat), how could I go about proving this?This problem has been bugging me. I would greatly appreciate any help.ChrisBegin Python Program---------------rate = .1years = 50Over50 = [14000, 16000, 18000]Over50M = [18000, 20000, 22000]def GetSum(funds): result = [] total = 0.0 for x in range(years): if x < 2: total += funds[x] else: total += funds[-1] total *= (1.0 + rate) result.append(total) return resultdef PrintResults(a, b): print ?Year', ?t', ?Unmatched', ?t', ?Matched', ?t', 'Unmatched -matched' for x in range(years): unmat = a[x] * .85 mat = b[x] * .65 print (x+1), ?t', unmat, ?t', mat, ?t', unmat - matresultOver50 = GetSum(Over50)resultOver50M = GetSum(Over50M)PrintResults(resultOver50, resultOver50M) === > I am trying to model two different savings plans here in the US, and> seem to be running into contradictory results.> There are two plans, an unmatched plan and a matched plan.> You can add money to the unmatched plan like so:> 2004: 16k> 2005: 18k (it remains at 18k from here on)> Then there is a matched plan (the employer adds 4k)> 2004: 20k> 2005: 22k (it remains at 22k from here on)> When you withdraw your money, the unmatched plan is taxed at 15%,> while the matched plan is taxed at 35% (this tax is only applied once,> when withdrawing all the money). Assume 10% interest compounded> anually.> It initially appears that after several years, the extra 4k added over> and over again will make the matched plan more attractive. Apparently> the latest BusinessWeek mentioned something to this effect.> me contradictory results.> Approaching the problem mathematically, I solved for U_n and M_n (for> n > 2)> U_n = unmatched funds after n years> M_n = matched funds after n years> I determined the formulas to be:> U_n = 14000 * (1.1)^n + 16000 * (1.1)^(n-1) + 18000* (1.1^(n-1) -> 1.1)/(.1)> M_n = 18000 * (1.1)^n + 20000 * (1.1)^(n-1) + 22000* (1.1^(n-1) -> 1.1)/(.1)> The last terms of each equation are a simpli?d geometric series> I want n, such that .85 * U_n = .65 * M_n. How do I solve for n?You don't. As you observed, they are never equal.[...]U_n = 14000*A + 16000*B + 18000*K;M_n = 18000*A + 20000*B + 22000*K;0.85*U_n = 11900*A + 13600*B + 15300*K;0.65*M_n = 11700*A + 13000*B + 14300*K.And A, B and K are positive (I don't agree with your K but it doesn'tmatter).So unmatched, taxed at 15% is always better that matched at 35%.-- Paul SperryColumbia, SC (USA) === >I am trying to model two different savings plans here in the US, and>seem to be running into contradictory results.>>There are two plans, an unmatched plan and a matched plan.>>You can add money to the unmatched plan like so:>2004: 16k>2005: 18k (it remains at 18k from here on)>>Then there is a matched plan (the employer adds 4k)>2004: 20k>2005: 22k (it remains at 22k from here on)>>When you withdraw your money, the unmatched plan is taxed at 15%,>while the matched plan is taxed at 35% (this tax is only applied once,>when withdrawing all the money). Assume 10% interest compounded>anually.>Where do you get these tax rates? I'll bet the difference isn't the calculations, it's the assumptions.Is it possible that the unmatched plan paid with after-tax dollars, so that some percentage is going to taxes (or you're really making bigger contributions)? Maybe the best thing to do is give us the generic names of the plans, like Roth IRA vs. employer-sponsered 401(k) plan.The rates also depend on income. You need to use your (foreknown) marginal tax rate for the years you're going to be withdrawing the money.Keeping the rest because downthread comments may refer to them.Jon Miller>It initially appears that after several years, the extra 4k added over>and over again will make the matched plan more attractive. Apparently>the latest BusinessWeek mentioned something to this effect.>>me contradictory results.>>Approaching the problem mathematically, I solved for U_n and M_n (for>n > 2)>>U_n = unmatched funds after n years>M_n = matched funds after n years>>I determined the formulas to be:>>U_n = 14000 * (1.1)^n + 16000 * (1.1)^(n-1) + 18000* (1.1^(n-1) ->1.1)/(.1)>M_n = 18000 * (1.1)^n + 20000 * (1.1)^(n-1) + 22000* (1.1^(n-1) ->1.1)/(.1)>>The last terms of each equation are a simpli?d geometric series>>I want n, such that .85 * U_n = .65 * M_n. How do I solve for n?>>If you see any obvious problems with my program, feel free to point>them out.>>If the funds never equal each other (which is what my program hints>at), how could I go about proving this?>>This problem has been bugging me. I would greatly appreciate any help.>>Chris>>Begin Python Program>--------------->>rate = .1>years = 50>>Over50 = [14000, 16000, 18000]>Over50M = [18000, 20000, 22000]>>def GetSum(funds):> result = []> total = 0.0> for x in range(years):> if x < 2:> total += funds[x]> else:> total += funds[-1]> total *= (1.0 + rate)> result.append(total)> return result>>def PrintResults(a, b):> print ?Year', ?t', ?Unmatched', ?t', ?Matched', ?t', 'Unmatched ->matched'> for x in range(years):> unmat = a[x] * .85> mat = b[x] * .65> print (x+1), ?t', unmat, ?t', mat, ?t', unmat - mat>>resultOver50 = GetSum(Over50)>resultOver50M = GetSum(Over50M)>>PrintResults(resultOver50, resultOver50M)> === Can anyone help with the following....I've been given a function h(x) = 1/1600 x, x>=0and told that the function Q(x) = exp (- integral between x and 0 h(u) du)I've evaluated this to e ^ -1/3200x^2Is this right - my integration is VERY rusty.I've then worked out that the CDF of X isF(x) = 1 -Q(x) = 1 - e ^ -1/3200x^2Hence the pdf isf(x) = 1/3200 e ^-1/3200x^2Which has given me an exponential distribution with lambda = square root1/3200 ( I've square rooted cos of the ^2 term in e above) giving a mean of56.56854249 (1/lambda)Can someone just check my calculations === > Can anyone help with the following....>> I've been given a function h(x) = 1/1600 x, x>=0> and told that the function Q(x) = exp (- integral between x and 0 h(u) du)>> I've evaluated this to e ^ -1/3200x^2> Is this right - my integration is VERY rusty.>integral(0,x) 1/1600u du = (log u)/1600 |0,x which gives problem at u = 0integral(0,x) (1/1600)u du = (1/2)(1/1600)u^2 |0,x = x^2 / 3200 = (x^2)/3200Becareful about 1/2 u, 1/2u, (1/2)u, 1/(2u)> I've then worked out that the CDF of X is> F(x) = 1 -Q(x)> = 1 - e ^ -1/3200x^21 - e^[(-1/3200)x^2]It appeared you said 1 - e^[-1/(3200x^2)]Beware e^a+b, e^a + b, e^(a+b), (e^a) + b.[clip]>> Can someone just check my calculations>The problem I see is lack of clarity writing formulas in one line ascii. === Debbie Sewell :> I've been given a function h(x) = 1/1600 x, x>=0> and told that the function Q(x) = exp (- integral between x and 0 h(u) du)> I've evaluated this to e ^ -1/3200x^2> Is this right - my integration is VERY rusty.> I've then worked out that the CDF of X is> F(x) = 1 -Q(x)> = 1 - e ^ -1/3200x^2> Hence the pdf is> f(x) = 1/3200 e ^-1/3200x^2> Which has given me an exponential distribution with lambda = square root> 1/3200 ( I've square rooted cos of the ^2 term in e above) giving a mean of> 56.56854249 (1/lambda)Close, but be careful with the details. This problem is formally identical to ?ding the event density givena hazard function in survival analysis. That doesn't help solve integrals,It looks to me like you're OK up to and including the calculation ofF(x) = 1 - exp(-(1/3200) x^2). Recall that the derivative of exp(y(x))is y'(x) exp(y(x)) where y(x) is some function of x. So we have f(x) = -(d/dx) (-(1/3200) x^2) exp(-(1/3200) x^2) = (x/1600) exp(-(1/3200) x^2)de?itions given, this is always the case: the hazard function is the ratio of the event density to the survival function.Note that this density f(x) is not an exponential density; an exponential event density has a constant (not linear) hazard function.The expected value of the event density is integral(0,inf) x f(x) dx,which you can solve by integration by parts. Recall that (d/dx) exp(x^2)is just 2 x exp(x^2).Hope this helps,Robert Dodier--If I have not seen as far as others, it is because giants werestanding on my shoulders. -- Hal Abelson === > Debbie Sewell :>> I've been given a function h(x) = 1/1600 x, x>=0>> and told that the function Q(x) = exp (- integral between x and 0 h(u)du)>> I've evaluated this to e ^ -1/3200x^2> Is this right - my integration is VERY rusty.>> I've then worked out that the CDF of X is> > F(x) = 1 -Q(x)> = 1 - e ^ -1/3200x^2> Hence the pdf is> > f(x) = 1/3200 e ^-1/3200x^2>> Which has given me an exponential distribution with lambda = square root> 1/3200 ( I've square rooted cos of the ^2 term in e above) giving a meanof> 56.56854249 (1/lambda)>> Close, but be careful with the details.>> This problem is formally identical to ?ding the event density given> a hazard function in survival analysis. That doesn't help solve integrals,>> It looks to me like you're OK up to and including the calculation of> F(x) = 1 - exp(-(1/3200) x^2). Recall that the derivative of exp(y(x))> is y'(x) exp(y(x)) where y(x) is some function of x. So we have>> f(x) = -(d/dx) (-(1/3200) x^2) exp(-(1/3200) x^2)> = (x/1600) exp(-(1/3200) x^2)>> de?itions given, this is always the case: the hazard function> is the ratio of the event density to the survival function.>> Note that this density f(x) is not an exponential density; an> exponential event density has a constant (not linear) hazard function.>> The expected value of the event density is integral(0,inf) x f(x) dx,> which you can solve by integration by parts. Recall that (d/dx) exp(x^2)> is just 2 x exp(x^2).>> Hope this helps,> Robert Dodier> --> If I have not seen as far as others, it is because giants were> standing on my shoulders. -- Hal Abelsonintegration above x^2 etc.. !!So, can you help me with the step by step way of using integration by partsfor integral(0,inf) exp(-(1/3200) x^2). ??Debbie === Is there a way to completely describe the isomorphisms from Z_p x Z_q(where p and q are any integers, not necessarily relatively prime) toitself? What are these automorphisms? === >Is there a way to completely describe the isomorphisms from Z_p x Z_q>(where p and q are any integers, not necessarily relatively prime) to>itself? What are these automorphisms?Well, since any ?ite abelian group G is the direct product of its Sylowsubgroups P_1,...,P_r, and Aut(G) = Aut(P_1) x ... x Aut(P_r), this problemimmediately reduces to the case when p amnd q are both powers of the sameprime - so let's change notation, and consider A = Aut(G), withG = Z_{p^a} x Z_{p^b}, where p is prime and 0 <= a <= b.In all cases, A has a normal p-subgroup N which acts trivially on G/G^p,and A/N is the induced action of A on G/G^p. I did a quick calculation,(and may have made mistakes!), and gotCase 1. a = 0, G is cyclic. This case is well known. |N| = p^(b-1) and |A/N| = p-1.Case 2. 0 < a < b. |N| = p^(3a+b-2), |A/N| = (p-1)^2.Case 3. 0 < a = b. |N| = p^(4(a-1)), |A/N| = |GL(2,p)| = (p^2-1)(p^2-p).I am sure the structure could be described more precisely if necessary.I believe that I have seen it in the literature.Derek Holt. === > Is there a way to completely describe the isomorphisms from Z_p x Z_q> (where p and q are any integers, not necessarily relatively prime) to> itself? What are these automorphisms?I know of no nice description for arbitrary p and q.Hom(Z_p x Z_q, Z_p x Z_q) is isomorphic toHom(Z_p, Z_p) x Hom(Z_p, Z_q) x Hom(Z_q, Z_p) x Hom(Z_q, Z_q).The ?st and last Hom's are isomorphic to Z_p and Z_q respectively.Thetwo mixed Hom's depend strongly on how p and q are related. Moreover,it is not obvious (to me, anyway) how to identify the images of theautomorphisms of Z_p x Z_q in the product of the Hom's.-- Paul SperryColumbia, SC (USA) === > Is there a way to completely describe the isomorphisms from Z_p x Z_q> (where p and q are any integers, not necessarily relatively prime) to> itself? What are these automorphisms?(I shall use the notation Z/p and Z/q instead of Z_p and Z_q)Further, and in contrast to Derek Holt's more enlightened approach, Ihave an elementary prime-free description of the situation.Let g = gcd(p, q), and p' = p/g, q' = q/g.Let e_1 and e_2 be generators of Z/p x Z/q, with orders p and qrespectively.Then one can represent the endomorphism ring of Z/p x Z/q as the ringof 2x2 matricesa b = Ac dsuch thata belongs to Z/p,b belongs to Z/p and is a multiple of p'c belongs to Z/q and is a multiple of q'd belongs to Z/q.These matrices act on the group in a natural way, and also multiplynaturally to represent composition.Necessary conditions for such a matrix A to represent an automorphism(i.e. to be invertible) are(1) gcd(det A, p, q) = 1.(2) gcd(a, p') = 1(3) gcd(d, q') = 1Conversely, suppose that A satis?s all three conditions. Let A' bethe reduction of A mod g. Then (1) tells us that A' is invertible,with inverse B', say. We want to construct a matrix B of the aboveform which reduces to B' mod g. Well, the non-diagonal entries of B'determine those of B. Then apply the Chinese remainder theorem to getthe diagonal entries of B, and hopefully a simple calculation shouldshow that the matrix we construct is indeed the inverse of A. === T H O M A S20 8 15 13 1 19 = 76 I met Joshua in Bessborough Park beside the drinking fountain.76+ Mom 16 7 53 197/168 +1312289 Joshua 4 8 81 216/149 8934Joshua 74 Christopher 139 Thomas 76 Joshua is a 6 lettered name, Joshua is Bible Book 6, Joshua adds to74 (a factor of 666). Joshua begins with the 10th letter of thealphabet (6th non-prime). The vowels and consonants in Joshua both addnon-prime). Joshua was born on the 216th (6x6x6th) day of the year, itis the 13x13th non-prime (while 13 in turn is the 6th prime). Joshua(Book 6) contains 24 (6+6+6+6) chapters, I am 24 years older thanJoshua.1-50 - Genesis51-90 - Exodus91-117 - Leviticus118-153 - Numbers154-187 - Deuteronomy188-211 - Joshua930-957 - Matthew958-973 - Mark974-997 - Luke998-1018 - John1019-1046 - Acts1047-1062 - Romans 188 <-the opening chapter of Book 6 is 6x6x6 short of the 404 verses of Bible Book 66, it is the 6th prime squared (13x13) short of the 357 verses of Daniel (also in part about 666) 193 <-Book 6 chapter 6 is the 44th prime, while 44 is in turn 66.666...% of 66 211 <-the terminating chapter of Book 6 is approximately 66.6% of the 66th prime (317) 357 <-the opening chapter of Book 6 plus the 6th prime squared is the 357 verses of Daniel (in part about 666) 404 <-the 6th prime squared (13x13) plus the 6th prime squared (13x13) plus 66 adds to the 404 verses of Bible Book 661062 <-666 plus 6x66 is a combination of the 658 verses of Bible Book 6 plus the 404 verses of Bible Book 66, and is the terminating chapter of New Testament Book 61070 <-666 plus the 404 verses of Book 66 is the 1070 verses of Job (Book 6+6+6)1213 <-Exodus terminates at chapter 90 (66th non- prime) with 1213 verses (the 198th or the 66+66+66th prime)1292 <-the 658 verses of Book 6 plus twice the 66th prime (317) is the 1292 verses of Isaiah (the Book contains 66 chapters) Mom was born on the 16th day of the month, perhaps in 53 (16thprime), and she gave birth on the 216th day of the year. She gavebirth with 149 days remaining in the year, it's the length of BibleBook 48 (16+16+16). Joshua's name adds to 289, corresponding to the(166th non-prime).Primes Non-Primes 2 1 3 4 5 6 7 8 11 9 13 10 17 12 19 14 23 15 29 16 31 18 37 20 41 21 43 22 47 24 53 25 59 26 61 27 67 28 71 30 73 32 79 33 83 34 89 35 97 36 101 38 103 39 107 40 109 42 113 44 127 45 131 46 137 48 139 49 149 50 151 51 157 52 163 54 167 55 173 56 179 57 181 58 191 60 193 62 197 63 199 64 211 65 223 <-48th-> 66---- ---4661 1710 Joshua was born with 149 days remaining in the year, it's thethe 48th prime (223) and the 48th non-prime (66). Primes In Prime Primes Positions 1 2 2 3 <- 3 3 5 <- 5 4 7 5 11 <- 11 6 13 7 17 <- 17 8 19 9 2310 2911 31 <- 3112 3713 41 <- 41 --- 108 Mom and Joshua were born on days of the year adding to 413, it isexactly 59 weeks (the 17th prime). Joshua was born in 81 (59thnon-prime while 59 is the 17th prime). He was born a multiple of 17days into the century (29801=17x1753). Mom and Joshua were togetherborn a multiple of 108 days into the century (49356=108x457), thereare 108 verses in Bible Book 59 (the 17th prime, it's the 17th primeday, month and year of birth adds to 93 (Leviticus 3 with 17 verses).plus the 17th prime, chapter 76 is Exodus 26 (17th non-prime). Todaymom and Joshua are together 71.77 years old. Primes In Prime Primes Positions 1 2 2 3 <- 3 3 5 <- 5 4 7 5 11 <- 11 6 13 7 17 <- 17 8 19 9 2310 2911 31 <- 3112 3713 41 <- 4114 4315 4716 5317 59 <- 59 --- 167 Esther Book 17 Joshua was born 19 days after mom's birthday. Mom was born on day197, it's the number of verses in Bible Book 28 (19th non-prime).Mom's day, month and year of birth adds to 76 and she married Thomas(76=4x19). Joshua was born 67 days closer to the end of the year thanto the beginning of the year (19th prime), and keep in mind that the2460 verses of Bible Book 19 is19x19+19x19+19x19+19x19+19x19+19x19+19x19 minus the 19th prime (67).unrepeated letters add to 77 (the primes up to 19). Mom was born onthe 19555th day of the century and married Thomas (76, the 55thnon-prime). The Samuels are Books 9 and 10 (for 19) with 55 chaptersand 1505 verses. I criticized churches (I said they had Egyptian penises on theirroofs, and this was in opposition to God's Second Commandment),Protestants and Catholics lobbied my abusive parents to have metreated, my abusive parents quickly complied and I was repeatedlyProtestants and Catholics then sat on psychiatric appeal paneldetain and torture me. I begged and begged for assistance to get outof the country to no avail, people would tell me that I was there (inpsychiatric facilities) because I was supposed to be there. And so itis with Joshua, he now ?ds himself posted on the usenet becuase heis supposed to be here. I showed Joshua gems, and like everybody else,he was so cheap and ignorant that he did not even have the decency totime out of my life to do so. But come December, he will please hisparents (or his girlfriend's parents) and attend their church, he willcomment on the beauty of their decorated trees or their steeple (arepresntation of a penis), and will give them money (the churches thatteach you people to turn pagan fertility symbols into decorated idolsare supposedly worthy of your support and respect). In my effort toget out of the brutal cycle of psychiatric abuuse, I told theProtestants and Catholics seated in judgment against me that the Biblerepeatedly condemns turning trees into idols, and that they in factbow to their decorated trees via the placement and retieval ofpresents at the base of their trees. At one psychiatric appeal panelhearing Dr. Gene Marcoux heard me say this, he responded by sayingthat I was religiously deluded to believe this, and then all theProtestants and Catholics nodded in agreement and gave him permissonto detain and torture me for the following three weeks. Year afteryear you people collectively spend billions of dollars on turningtrees into decorated idols, you have spent millions of dollars havingme tortured in an attempt to make me shut up about this and othertraditions being taught by your churches, and you are so cheap andignorant that you can't even offer to pay me minimum wage for my workso I could attempt to get out of this country on my own dime. I wasfrantic to leave the country as I lost summer after summer aftersummer after summer after summer after summer after summer topsychiatric torture, and the subsequent summers were effectly lost aswell as I remained frantic to leave the country (I expected to bearrested and tortured in the years that I was not), and there isn't asingle person who has the compassion to assist me to get out of thiscountry for one single winter!!! You are the shit of the earth JoshuaChristopher Thomas, you are an incompassionate turd, and now I beg Godto honor Exodus 20:5 and Hosea 4:6 as promises so that He wouldterminate your life, or at least turn away from you in your hour ofneed. If I hear of your death I will cheer with utter glee, it will bein accordance to Scripture (Psalm 137:9), and I will post your statsagain. God is about to spread you people out like dung over thesurface of the earth, and in this I rejoice. You have billions ofdollars to spend on turning trees into idols, you have millions ofand so ignorant that you can't even buy a postage stamp in order tosend me a cheap letter expressing thanx for showing you evidence thatyour very name is a gift from God.Daryl Shawn KabatoffBox 7134Saskatoon SaskatchewanCanadaS7K 4J1Isaiah 45:4, Ephesians 3:15 - God gives you your name!!! === T H O M A S20 8 15 13 1 19 = 76 I met Joshua in Bessborough Park beside the drinking fountain.76+ Mom 16 7 53 197/168 +1312289 Joshua 4 8 81 216/149 8934Joshua 74 Christopher 139 Thomas 76 Joshua is a 6 lettered name, Joshua is Bible Book 6, Joshua adds to74 (a factor of 666). Joshua begins with the 10th letter of thealphabet (6th non-prime). The vowels and consonants in Joshua both addnon-prime). Joshua was born on the 216th (6x6x6th) day of the year, itis the 13x13th non-prime (while 13 in turn is the 6th prime). Joshua(Book 6) contains 24 (6+6+6+6) chapters, I am 24 years older thanJoshua.1-50 - Genesis51-90 - Exodus91-117 - Leviticus118-153 - Numbers154-187 - Deuteronomy188-211 - Joshua930-957 - Matthew958-973 - Mark974-997 - Luke998-1018 - John1019-1046 - Acts1047-1062 - Romans 188 <-the opening chapter of Book 6 is 6x6x6 short of the 404 verses of Bible Book 66, it is the 6th prime squared (13x13) short of the 357 verses of Daniel (also in part about 666) 193 <-Book 6 chapter 6 is the 44th prime, while 44 is in turn 66.666...% of 66 211 <-the terminating chapter of Book 6 is approximately 66.6% of the 66th prime (317) 357 <-the opening chapter of Book 6 plus the 6th prime squared is the 357 verses of Daniel (in part about 666) 404 <-the 6th prime squared (13x13) plus the 6th prime squared (13x13) plus 66 adds to the 404 verses of Bible Book 661062 <-666 plus 6x66 is a combination of the 658 verses of Bible Book 6 plus the 404 verses of Bible Book 66, and is the terminating chapter of New Testament Book 61070 <-666 plus the 404 verses of Book 66 is the 1070 verses of Job (Book 6+6+6)1213 <-Exodus terminates at chapter 90 (66th non- prime) with 1213 verses (the 198th or the 66+66+66th prime)1292 <-the 658 verses of Book 6 plus twice the 66th prime (317) is the 1292 verses of Isaiah (the Book contains 66 chapters) Mom was born on the 16th day of the month, perhaps in 53 (16thprime), and she gave birth on the 216th day of the year. She gavebirth with 149 days remaining in the year, it's the length of BibleBook 48 (16+16+16). Joshua's name adds to 289, corresponding to the(166th non-prime).Primes Non-Primes 2 1 3 4 5 6 7 8 11 9 13 10 17 12 19 14 23 15 29 16 31 18 37 20 41 21 43 22 47 24 53 25 59 26 61 27 67 28 71 30 73 32 79 33 83 34 89 35 97 36 101 38 103 39 107 40 109 42 113 44 127 45 131 46 137 48 139 49 149 50 151 51 157 52 163 54 167 55 173 56 179 57 181 58 191 60 193 62 197 63 199 64 211 65 223 <-48th-> 66---- ---4661 1710 Joshua was born with 149 days remaining in the year, it's thethe 48th prime (223) and the 48th non-prime (66). Primes In Prime Primes Positions 1 2 2 3 <- 3 3 5 <- 5 4 7 5 11 <- 11 6 13 7 17 <- 17 8 19 9 2310 2911 31 <- 3112 3713 41 <- 41 --- 108 Mom and Joshua were born on days of the year adding to 413, it isexactly 59 weeks (the 17th prime). Joshua was born in 81 (59thnon-prime while 59 is the 17th prime). He was born a multiple of 17days into the century (29801=17x1753). Mom and Joshua were togetherborn a multiple of 108 days into the century (49356=108x457), thereare 108 verses in Bible Book 59 (the 17th prime, it's the 17th primeday, month and year of birth adds to 93 (Leviticus 3 with 17 verses).plus the 17th prime, chapter 76 is Exodus 26 (17th non-prime). Todaymom and Joshua are together 71.77 years old. Primes In Prime Primes Positions 1 2 2 3 <- 3 3 5 <- 5 4 7 5 11 <- 11 6 13 7 17 <- 17 8 19 9 2310 2911 31 <- 3112 3713 41 <- 4114 4315 4716 5317 59 <- 59 --- 167 Esther Book 17 Joshua was born 19 days after mom's birthday. Mom was born on day197, it's the number of verses in Bible Book 28 (19th non-prime).Mom's day, month and year of birth adds to 76 and she married Thomas(76=4x19). Joshua was born 67 days closer to the end of the year thanto the beginning of the year (19th prime), and keep in mind that the2460 verses of Bible Book 19 is19x19+19x19+19x19+19x19+19x19+19x19+19x19 minus the 19th prime (67).unrepeated letters add to 77 (the primes up to 19). Mom was born onthe 19555th day of the century and married Thomas (76, the 55thnon-prime). The Samuels are Books 9 and 10 (for 19) with 55 chaptersand 1505 verses. I criticized churches (I said they had Egyptian penises on theirroofs, and this was in opposition to God's Second Commandment),Protestants and Catholics lobbied my abusive parents to have metreated, my abusive parents quickly complied and I was repeatedlyProtestants and Catholics then sat on psychiatric appeal paneldetain and torture me. I begged and begged for assistance to get outof the country to no avail, people would tell me that I was there (inpsychiatric facilities) because I was supposed to be there. And so itis with Joshua, he now ?ds himself posted on the usenet because heis supposed to be here. I showed Joshua gems, and like everybody else,he was so cheap and ignorant that he did not even have the decency totime out of my life to do so. But come December, he will please hisparents (or his girlfriend's parents) and attend their church, he willcomment on the beauty of their decorated trees or their steeple (arepresentation of a penis), and will give them money (the churchesthat teach you people to turn pagan fertility symbols into decoratedidols are supposedly worthy of your support and respect). In my effortto get out of the brutal cycle of psychiatric abuse, I told theProtestants and Catholics seated in judgment against me that the Biblerepeatedly condemns turning trees into idols, and that they in factbow to their decorated trees via the placement and retrieval ofpresents at the base of their trees. At one psychiatric appeal panelhearing Dr. Gene Marcoux heard me say this, he responded by sayingthat I was religiously deluded to believe this, and then all theProtestants and Catholics nodded in agreement and gave him permissionto detain and torture me for the following three weeks. Year afteryear you people collectively spend billions of dollars on turningtrees into decorated idols, you have spent millions of dollars havingme tortured in an attempt to make me shut up about this and othertraditions being taught by your churches, and you are so cheap andignorant that you can't even offer to pay me minimum wage for my workso I could attempt to get out of this country on my own dime. I wasfrantic to leave the country as I lost summer after summer aftersummer after summer after summer after summer after summer topsychiatric torture, and the subsequent summers were effectively lostas well as I remained frantic to leave the country (I expected to bearrested and tortured in the years that I was not), and there isn't asingle person who has the compassion to assist me to get out of thiscountry for one single winter!!! You are the shit of the earth JoshuaChristopher Thomas, you are an incompassionate turd, and now I beg Godto honor Exodus 20:5 and Hosea 4:6 as promises so that He wouldterminate your life, or at least turn away from you in your hour ofneed. If I hear of your death I will cheer with utter glee, it will bein accordance to Scripture (Psalm 137:9), and I will post your statsagain. God is about to spread you people out like dung over thesurface of the earth, and in this I rejoice. You have billions ofdollars to spend on turning trees into idols, you have millions ofand so ignorant that you can't even buy a postage stamp in order tosend me a cheap letter expressing thanx for showing you evidence thatyour very name is a gift from God.Daryl Shawn KabatoffBox 7134Saskatoon SaskatchewanCanadaS7K 4J1Isaiah 45:4, Ephesians 3:15 - God gives you your name!!! === Lately I've been explaining how I found an error in taught mathematicsas I prove that in the ring of algebraic integers a number I'll herecall x has a factor I'll here call y, but x/y is not an algebraicinteger.Now at least *some* of you should be wondering how that works giventhat division is not a ring operation.Part of the problem for those of you who wonder about that is that themathematicians among you probably know how that all plays out as I'vebeen arguing for a while now, but a poster named Randy Poe posted somethings that lead me to consider that all of you aren't necessarilymath experts i.e. mathematicians.Ok, here it goes. I'm going to go kind of fast but you should be ableto keep up as it's simple.First thing is my paper Advanced Polynomial Factorization which is asusual found at http://groups.msn.com/AmateurMathshows that given these three numbers two of them have this factor Icall f and the ring is algebraic integers.That's all you get there, and there's no mention of anything likex/y, which I've talked about a lot.And there's no mention because the ring operations are addition andmultiplication.Division is not a ring operation. Division is de?ed for ?lds, notrings.So then, it's *provable* that a number I'll call x has a factor I'llcall y in the ring of algebraic integers, is what the paper covers. There you have the a's like before and two of the a's have a factor f,while the third is coprime to f, which is proven in the paper.That is, given the de?ition for algebraic integer I can prove thatthere's this number I'll call x, which is itself an algebraic integer,that has this number I'll call y, which is an algebraic integer, as afactor.That's it for the paper.Now then, taking that result in that ring, I can now move to the ?ldof algebraic numbers.Now I have division, and in that ?ld, I take x/y and notice thatit's NOT an algebraic integer, which is a contradiction.That's how it's done.Now for the mathematicians, what I just said shouldn't be news, but alot of you are basically, um, what's the right word? Well thereprobably isn't a right word so I'll leave it there.Notice I'm only posting to sci.math and alt.math.undergrad here, as Idon't see the point in bothering anyone else with such trivialdetails.James Harris === [...]> Now then, taking that result in that ring, I can now move to the ?ld> of algebraic numbers.> Now I have division, and in that ?ld, I take x/y and notice that> it's NOT an algebraic integer, which is a contradiction.> That's how it's done.The ?ld of algebraic numbers over the rationals Q contains the ringof algebraic integers over Q, but the two are not equal.So if x and y are algebraic integers over Q, and y is not zero,then surely x/y is an algebraic number. By no means doesx, y algebraic integers imply x/y is an algebraic integer.David Bernier === > Lately I've been explaining how I found an error in taught mathematics> as I prove that in the ring of algebraic integers a number I'll here> call x has a factor I'll here call y, but x/y is not an algebraic> integer.> Can you explain what you mean by factor in this instance?For example, 3 and 5 are algebraic integers, but 3/5 is not an algebraic integer. That's because the algebraic integers are a ring but not a ?ld. What do you mean that y is a factor of x? If x and y are algebraic integers, the accepted de?ition of factor is that there is some algebraic integer z such that yz = x. If so, then we say that y is a factor of x.If we consider the example above in the ring of the usual integers, 5 is not a factor of 3. But if we extend the ring of integers to the ?ld of rationals, it turns out that there is a rational, namely 3/5, with the property that 5 * 3/5 = 3. The same example works in the ring of algebraic integers.So all you seem to be saying is that you've determined that the algebraic integers are a ring but not a ?ld. This is already well known.Is this what you're talking about? === >Lately I've been explaining how I found an error in taught mathematics>as I prove that in the ring of algebraic integers a number I'll here>call x has a factor I'll here call y, but x/y is not an algebraic>integer.>[...]>>Now then, taking that result in that ring, I can now move to the ?ld>of algebraic numbers.>>Now I have division, and in that ?ld, I take x/y and notice that>it's NOT an algebraic integer, which is a contradiction.No, that's not a contradiction. Because you get a factor in the?ld of algebraic numbers, _not_ in the algebraic integers.The following looks like one of those nasty parodies peoplesometimes post, but actually it's an illustration of _exactly_the error you're making, translated to a more familiar context:Lately I've been explaining how I found an error in taughtmathematics as I prove that in the ring of integers a number I'll here call x has a factor I'll here call y, but x/y is not aninteger.Let x = 2, y = 3.Now then, taking that result in that ring, I can now move to the ?ldof rational numbers.Now I have division, and in that ?ld, I take x/y and notice thatit's NOT an integer, which is a contradiction.Honest. What you're saying here makes _exactly_ as muchsense as saying that 3 is a factor of 2 (because 2/3 existsin the rationals) although 2/3 is not an integer, contradiction.There's no contradiction, just two true facts:(i) 3 is _not_ a factor of 2, _in_ the integers.(ii) 3 _is_ a factor of 2 _in_ the rationals (and luckily 2/3 is rational.)************************David C. Ullrich === > Lately I've been explaining how I found an error in taught mathematics> as I prove that in the ring of algebraic integers a number I'll here> call x has a factor I'll here call y, but x/y is not an algebraic> integer.> > Can you explain what you mean by factor in this instance?> For example, 3 and 5 are algebraic integers, but 3/5 is not an algebraic > integer. That's because the algebraic integers are a ring but not a > ?ld. > What do you mean that y is a factor of x? If x and y are algebraic > integers, the accepted de?ition of factor is that there is some > algebraic integer z such that yz = x. If so, then we say that y is a > factor of x.> If we consider the example above in the ring of the usual integers, 5 is > not a factor of 3. But if we extend the ring of integers to the ?ld > of rationals, it turns out that there is a rational, namely 3/5, with > the property that 5 * 3/5 = 3. > The same example works in the ring of algebraic integers.> So all you seem to be saying is that you've determined that the > algebraic integers are a ring but not a ?ld. This is already well > known.> Is this what you're talking about?This is going to seem rather odd. There are times when I thinkwe put too much stress on form and not enough on substance. Allowing for the fact that James Harris activelyresists the use of standard terminology and wants to remainignorant of conventions and de?itions, is there any waythat his statement about x and y could make sense?I think so. If x and y are algebraic integers and y isa factor of x in the algebraic integers, anyone wouldnaturally conclude that x/y must be an algebraic integer simply from the de?ition of factor. But there is still the possibility that x/y could be a root of a non-monic polynomial with integer coef?ients, primitive and irreducible over the rationals: that is, that possibility would exist if it were not for the following known theorem: Theorem. If r is a root of a non-monic polynomial with integer coef?ients that is primitive and irreducible over the rationals, then r cannot be an algebraic integer.Now if Harris could show that x/y is such a root, onewould have to conclude that either (1) the theorem aboveis wrong, or (2) something else is wrong with coremathematics, i.e., the mathematics that is currentlytaught.Harris argued for many months that the Theorem is wrong.He tried over and over again to come up with a counter-example. He ?ally consented to read a proof of thetheorem, *only after* someone that he regarded as anauthority, Robert Israel, stated that the theorem wasvalid. He then said that he accepted the theorem. Whether he ever actually read the proof I don't know.However it appears now that he has slid back to grinding thisold axe in a new form: he no longer says the theoremis wrong; instead he says there is something wrong withcore mathematics and in particular something wrong with the de?ition of algebraic integers, or that thering of algebraic integers is incomplete.The point here is, there is possible content in whathe says. I totally disagree with his conclusion, butit could make a loony kind of sense. If he actually did?d x and y as above, and a non-monic polynomial with integer coef?ients, primitive and irreducibleover the rationals with the algebraic integer x/y as a root, he would indeed have found something wrong with mathematics. Of course he hasn't, but theoretically it could make sense.Thus: quit taking him to task for the super?ial problemof not knowing the de?ition of ?factor'. Take him to task for yet again trying to show that the Theorem above, which he has accepted, is false. Ask him to specify the non-monic polynomial of which x/y is a root.Andrzej === > What do you mean that y is a factor of x? If x and y are algebraic > integers, the accepted de?ition of factor is that there is some > algebraic integer z such that yz = x. If so, then we say that y is a > factor of x.[snip]> This is going to seem rather odd. There are times when I think> we put too much stress on form and not enough on > substance. Allowing for the fact that James Harris actively> resists the use of standard terminology and wants to remain> ignorant of conventions and de?itions, is there any way> that his statement about x and y could make sense?> I think so. If x and y are algebraic integers and y is> a factor of x in the algebraic integers, anyone would> naturally conclude that x/y must be an algebraic > integer simply from the de?ition of factor.Uh, yeah.> But > there is still the possibility that x/y could be a root > of a non-monic polynomial with integer coef?ients, > primitive and irreducible over the rationals: that is, > that possibility would exist if it were not for the > following known theorem:> Theorem. If r is a root of a non-monic polynomial> with integer coef?ients that is primitive and > irreducible over the rationals, then r cannot be > an algebraic integer.Snip. You haven't clari?d the problem as far as I cansee. If the relationship between x and y is notx/y is an algebraic integer, then what is it?You seem to be saying that the only thing known aboutx/y is that it is the root of such a polynomial. That'seasy.> The point here is, there is possible content in what> he says.And what is that? I don't get what you're trying tosay. It seems to be that: (1) There exists x and y algebraic integers such that (2) r = x/y is not an algebraic integer, and (3) r is the root of a non-monic polynomial with integer coef?ients, that is primitive and irreducible over the rationals.Is that it? If so, isn't that just a trivial restatementof the theorem? - Randy === > What do you mean that y is a factor of x? If x and y are algebraic > integers, the accepted de?ition of factor is that there is some > algebraic integer z such that yz = x. If so, then we say that y is a > factor of x.> [snip]> This is going to seem rather odd. There are times when I think> we put too much stress on form and not enough on > substance. Allowing for the fact that James Harris actively> resists the use of standard terminology and wants to remain> ignorant of conventions and de?itions, is there any way> that his statement about x and y could make sense?> I think so. If x and y are algebraic integers and y is> a factor of x in the algebraic integers, anyone would> naturally conclude that x/y must be an algebraic > integer simply from the de?ition of factor.> Uh, yeah.> But > there is still the possibility that x/y could be a root > of a non-monic polynomial with integer coef?ients, > primitive and irreducible over the rationals: that is, > that possibility would exist if it were not for the > following known theorem:> Theorem. If r is a root of a non-monic polynomial> with integer coef?ients that is primitive and > irreducible over the rationals, then r cannot be > an algebraic integer.> Snip. You haven't clari?d the problem as far as I can> see. If the relationship between x and y is not> x/y is an algebraic integer, then what is it?> Obviously it is. What Harris may be trying to say is,I have found an algebraic integer which is a root of a*non-monic* polynomial etc., thus defying a well-knowntheorem. Therefore there is something wrong withmathematics: either the theorem is wrong (as he haslong contended) or the de?ition of algebraic integeris wrong, or something else. I am not sure why this needs explaining. I am veryde?itely not saying that I agree with Harris: simplythat instead of continuing to criticize him for refusingto recognize a tautology, consider that he may actuallyhave had something more in mind - something equally wrong,to be sure, but at a different level. I actually don't know how he goes from his main AdvancedPolynomial Factorization result (which has now beenproved false by two other posters) to obtaining x andy as he describes. I am not sure he remembers how either - not that it matters at all anyway. > You seem to be saying that the only thing known about> x/y is that it is the root of such a polynomial. That's> easy.> What??? Basically the monic criterion for algebraicintegers is if and only if - more precisely, an algebraicnumber is an algebraic integer if and only if its minimalpolynomial with integer coef?ients is monic.> The point here is, there is possible content in what> he says.> And what is that? I don't get what you're trying to> say. Yes, I see that.> It seems to be that:> (1) There exists x and y algebraic integers such that> (2) r = x/y is not an algebraic integer, and No - just the opposite - r = x/y IS an algebraic integer.> (3) r is the root of a non-monic polynomial with> integer coef?ients, that is primitive and irreducible> over the rationals.> Is that it? If so, isn't that just a trivial restatement> of the theorem?> Essentially he may be saying yet again, for the nth time,that he has found a counterexample to the theorem. The obvious question he should answer is: what is the polynomial? Andrzej > - Randy === > Obviously it is. What Harris may be trying to say is,> I have found an algebraic integer which is a root of a> *non-monic* polynomial etc., thus defying a well-known> theorem. Therefore there is something wrong with> mathematics: either the theorem is wrong (as he has> long contended) or the de?ition of algebraic integer> is wrong, or something else.OK, if he's made that statement. I thought you wereinterpreting the remarks about I have proved that x is afactor of y in the algebraic integers, but x/y is notan algebraic integer.Or perhaps you are. Is that his proof that x is afactor of y? I've never yet been able to ?ure outwhich part of James' writings are supposed to be theproof part, but every once in a while he startstalking as if a proof went by when nobody was looking. - Randy === > Obviously it is. What Harris may be trying to say is,> I have found an algebraic integer which is a root of a> *non-monic* polynomial etc., thus defying a well-known> theorem. Therefore there is something wrong with> mathematics: either the theorem is wrong (as he has> long contended) or the de?ition of algebraic integer> is wrong, or something else.> OK, if he's made that statement. I thought you were> interpreting the remarks about I have proved that x is a> factor of y in the algebraic integers, but x/y is not> an algebraic integer.> Or perhaps you are. Is that his proof that x is a> factor of y? I've never yet been able to ?ure out> which part of James' writings are supposed to be the> proof part, but every once in a while he starts> talking as if a proof went by when nobody was looking.> - Randy In connection of the x/y thing, he says he has foundproblems in core mathematics and taught mathematics -he has said the algebraic integers are incomplete(presumably as opposed to objects, where he has acircular de?ition and he has yet to identify even one object which is not an integer). My reply was none too clear, partly because I am notcertain of what he is implying. I he could be saying,I can prove that x/y is an algebraic integer but alsothe theorem implies that it's *not* an algebraic integer.Therefore something must be wrong with math. With regardto where the proof is in this case, as I said before, Idon't know and I am not sure he now knows. If it dependson his Advanced Polynomial Factorization paper, it isnowhere, per Hall and Baron. Andrzej === Ullrich, you're busted;you have a *lot* of explaining to do,to the Order of the Undead Mathematicians!> Lately I've been explaining how I found an error in taught> mathematics as I prove that in the ring of integers a number > I'll here call x has a factor I'll here call y, but x/y is not an> integer.> Let x = 2, y = 3.> Now then, taking that result in that ring, I can now move to the ?ld> of rational numbers.> Now I have division, and in that ?ld, I take x/y and notice that> it's NOT an integer, which is a contradiction.--A church-school McCrusade (Blair's ideals?):Harry-the-Mad-Potter want's US to kill Iraqis?...For a 1000-year anglo-american hegemony?HEY, JIMMY; LET'S US and SU FIGHT -then-PM of England & Zbiggyhttp://www.tarpley.net/bush25.htm (Thyroid Storm ch.) http://www.rwgrayprojects.com/synergetics/plates/plates.html http://quincy4board.homestead.com/?es/curriculum/Cosmo.PCX== ==Q. There is a Chinese steel company that produces steel rods for local construction company. The plant manager knew from past statistics that the rodsproduced are normally distributed with a mean length of 300cm. The standard deviation is 8cm. If 22% of the sample means are more than speci? lengthK, what is the value of K?Solution:Given: u = 300cm, sigma = 8cm, n = 14, p(>K)= 0.22Let K = be the length of the steel rodSince u (population) = u (sample) = 300, sigma (sample) = sigma /squareroot(14) = 2.138099P(bar X > K) = [K - u(sample)]/2.138099 = Zvalue(0.22)(K - 300) / 2.138089935 = Zvalue(0.22)(K - 300) / 2.138089935 = 0.58K = 2.138089935(0.58) + 300K = 301.2401cmTherefore, if 22% of the sample means are more than a speci? length K, then K is = 301.2401cm.Is my answer correct? === I am a cabinetmaker and a novice programmer. I have a interest in writinga plywood optimization application. This app takes a number of piecesof plywood and ?ds the best way to orient the pieces on a standardsheet size i.e. 4 x 8. I`m looking for a mathematical algorithm that dealswith this type of problem. I`m wondering if you might able to guide mein the right direction.Here is a link of a commercial product that provides a optimization ofplywood. http://www.sheetlayout.com/Best Wishes, Barry Golash === I tried to post this message before. I hope I'm not just being impatient and posting the same thing twice. Anyway, this is my question. Lets say I have y=f[x1(t),x2(t)] and I want to plot y(t) after removing the effect of x2 so that, in reality, I can have an idea of what x1(t) looks like. The data I have is y(t) (in which x1 and x2 are both taken into account) and x2(t). Ok, I hope I have made myself clear. === > I have y=f[x1(t),x2(t)] and I want to plot y(t) after removing the> effect of x2 so that, in reality, I can have an idea of what x1(t) looks> like. The data I have is y(t) (in which x1 and x2 are both taken into> account) and x2(t). Ok, I hope I have made myself clear.No, hardly at all. You want to plot, y = f(x1(t), x2(a)) to see whatx1(t) looks like? Oh, you have y(t) = f(x1(t), x2(t)) and want to ?dx1(t) from y(t) and x2(t) ?What if f(x,y) = g(y) ? Then y(t) = f(x1(t), x2(t)) = g(x2(t))and x1(t) could be anything and do anything it wanted as alongas y(t) and x2(t) were arbitrarly related as y(t) = g(x2(t)). === > I tried to post this message before. I hope I'm not just being impatient > and posting the same thing twice. Anyway, this is my question. Lets say > I have y=f[x1(t),x2(t)] and I want to plot y(t) after removing the > effect of x2 so that, in reality, I can have an idea of what x1(t) looks > like. The data I have is y(t) (in which x1 and x2 are both taken into > account) and x2(t). Ok, I hope I have made myself clear.In order to solve such a problem, you need to assume something aboutthe relationship between y, x1 and x2 (e.g. that x1 and x2 areindependent, and that y is dependent on both variables). In otherwords, you need to specify the problem more precisely. In particular,you must make an assumption about the functional relationship. Forexample, a common problem in linear system theory is that ofdeconvolution. i.e. assume y = x1 * x2, where * denotes convolution. The goal in that case would be to solve for x1 given x2 and y. Generally, this sort of problem falls under the category of aninverse problem. This is a very complicated subject with manypossible approaches. The chosen approach depends very much on yourparticular problem, and what you may assume about the relationshipbetween your variables x1, x2, and y. I hope this helps. === >>I tried to post this message before. I hope I'm not just being impatient >>and posting the same thing twice. Anyway, this is my question. Lets say >> I have y=f[x1(t),x2(t)] and I want to plot y(t) after removing the >>effect of x2 so that, in reality, I can have an idea of what x1(t) looks >>like. The data I have is y(t) (in which x1 and x2 are both taken into >>account) and x2(t). Ok, I hope I have made myself clear.> In order to solve such a problem, you need to assume something about> the relationship between y, x1 and x2 (e.g. that x1 and x2 are> independent, and that y is dependent on both variables). In other> words, you need to specify the problem more precisely. In particular,> you must make an assumption about the functional relationship. For> example, a common problem in linear system theory is that of> deconvolution. i.e. assume y = x1 * x2, where * denotes convolution.> The goal in that case would be to solve for x1 given x2 and y. > Generally, this sort of problem falls under the category of an> inverse problem. This is a very complicated subject with many> possible approaches. The chosen approach depends very much on your> particular problem, and what you may assume about the relationship> between your variables x1, x2, and y. I hope this helps.It does help. If nothing else, it lets me know that it wasn't as simple === By the way, I do know that y is dependent on both variables and that x1 and x2 are independent but that's about it. Oh, and I also have the following data: y vs t and x2 vs t. Anyway, like I said, I'll have to look into it some more.>>I tried to post this message before. I hope I'm not just being impatient >>and posting the same thing twice. Anyway, this is my question. Lets say >> I have y=f[x1(t),x2(t)] and I want to plot y(t) after removing the >>effect of x2 so that, in reality, I can have an idea of what x1(t) looks >>like. The data I have is y(t) (in which x1 and x2 are both taken into >>account) and x2(t). Ok, I hope I have made myself clear.> In order to solve such a problem, you need to assume something about> the relationship between y, x1 and x2 (e.g. that x1 and x2 are> independent, and that y is dependent on both variables). In other> words, you need to specify the problem more precisely. In particular,> you must make an assumption about the functional relationship. For> example, a common problem in linear system theory is that of> deconvolution. i.e. assume y = x1 * x2, where * denotes convolution.> The goal in that case would be to solve for x1 given x2 and y. > Generally, this sort of problem falls under the category of an> inverse problem. This is a very complicated subject with many> possible approaches. The chosen approach depends very much on your> particular problem, and what you may assume about the relationship> between your variables x1, x2, and y. I hope this helps. === > Lately I've been explaining how I found an error in taughtmathematics> as I prove that in the ring of algebraic integers a number I'll here> call x has a factor I'll here call y, but x/y is not an algebraic> integer.James,I tried to frame a de?ition of ?factor' in the thread ?Error in mypaper Advanced Polynomial Factorization'. I asked if my proposedde?ition was correct, but you did not respond. Is that de?itioncorrect?John Peters === >> Lately I've been explaining how I found an error in taught> mathematics> as I prove that in the ring of algebraic integers a number I'llhere> call x has a factor I'll here call y, but x/y is not an algebraic> integer.>> James,>> I tried to frame a de?ition of ?factor' in the thread ?Error in my> paper Advanced Polynomial Factorization'. I asked if my proposed> de?ition was correct, but you did not respond. Is that de?ition> correct?>> John PetersOops, posting under wrong pseudonym.Clive Tooth === <3c65f87.0306171917.10e891a3@posting.google.com>,> Oh yeah, it'd help if you know mathematics.> James HarrisIf who knew mathematics?