mm-33 === A mathematical proof begins with a truth, and proceeds by logical>steps to a conclusion which then must be true.>>I've pulled a detailed exposition of a short argument that quickly>shows a problem with algebraic integers. It starts after the>reference.Now here's a math proof. Those who doubt that fact can believe it's aclaim of proof, but it's verified to be a proof by tracing the>argument out.>> Not! See below.I've clipped sections where there was no claim of error by the posterNora Baron.>Essentially objections to how f^2 divides off now come down to>claiming that the w's are functions of m, but consider that w_1 w_2 =>1, when m=0, if f is coprime to 3.>>Now I'm focusing on what has been revealed to be an area of confusion.> Apparently some people believe that when I divide off f^2 that it can>divide off as a *function* of m, so that m=0 might be a special case. >I'm now starting the argument to address that belief by noting again>that w_1 w_2 = 1, when m=0, if f is coprime to 3. That is, when fdoesn't have 3 as a factor.>>But that was an arbitrary choice, so let f=3.>> f = 3 is irrelevant to what you want. There is> no reason to consider it. As you will see below, it> is a red herring and it does not show what you want. Which would imply that you are claiming that there is a misstep.However, f=3 shows that the w_1 w_2 = 3^{2/3} for ALL m, when f=3.However, w_1 w_2 is coprime to 3 when f is coprime to 3, at m=0.Therefore, the w's are not functions of m, and in fact w_1 w_2 iscoprime to f, for all m, and m=0 is not a special case.That is the conclusion that follows logically.Well having read down, the poster does have a point which in fact isthat the 3's divide off in an indeterminate way, so it's not so easyto just say that w_1 w_2 = 3^{2/3} because that could be the case, butthen again, maybe only w_3 has a factor of 3, so w_1 w_2 could stillbe coprime to 3. That is, I *said* f is coprime to 3 but in considering thispossibility it's worth it to relax that restriction and now consider>what would happen if it equals 3.>>Now w_1 w_2 = 3^{2/3} WITHOUT REGARD TO m. >>Seeing that is as simple as looking at>> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - >> 3(-1+mf^2 )x u^2 + u^3 f>>with f=3 as then you have> P(m)/3^2 = (m^3 3^4 - 3m^2 3^2 + 3m) x^3 - >> 3(-1+m3^2 )x u^2 + 3u^3>>so *every* coefficient has a factor that is 3, as you can tell by>looking.>> Let's look at this in detail when m = 1 and u = 1. Then> P(m)/3^2 = (81 - 27 + 3)*x^3 - 3*8*x + 3 > = 3*(19*x^3 - 8*x + 1).Ok.>So with>> P(m)/3^2 = (b_1 x + u w_1)(b_2 x + u w_2)(b_3 x + u w_3)>>each of the b's and each of the w's has a factor that is 3^{1/3},>while the b's can have additional factors in common with 3, the w's>cannot, as when 3 is separated out, notice you have>> P(m)/3^2 = 3((m^3 3^3 - 3m^2 3 + m) x^3 - >> (-1+m3^2 )x u^2 + u^3).>> As above when m = 1, u = 1, this is> 3*(19*x^3 - 8*x + 1).> The polynomial inside the parentheses can be factored> in the form> [1] (19*x^3 - 8*x + 1) = (b1*x + 1)*(b2*x + 1)*(b3*x + 1),> where b1, b2, and b3 are the negatives of the roots> of the associated polynomial> u^3 + 8*u^2 - 19.> Since the roots of the latter polynomial are algebraic> integers, one concludes b1, b2, and b3 are algebraic > integers also.> Now: how might you distribute the 3 in the expression> 3*(b1*x + 1)*(b2*x + 1)*(b3*x + 1) ?> Answer: LOTS of ways! There is no unique way. Here are> several:> 1. (b1*x + 1)*(b2*x + 1)*(3*b3*x + 3)> 2. (sqrt(3)*b1*x + sqrt(3))*(sqrt(3)*b2*x + sqrt(3)*(b3*x + 1)> 3. (3^{1/3}*b1*x + 3^{1/3})*(3^{2/3}*b2*x + 3^{2/3})*(b3*x + 1) 4. (3^{1/5}*b1*x + 3^{1/5})*(3^{3/5}*b2*x + 3^{3/5})> *(3^{1/5}*b3*x + 3{1/5})> In fact INFINITELY many ways. Any way you want to split 3 as a> product of three numbers gives a factorization. And in all the> examples just given (and in infinitely many others) note that (1) the> coefficients of the x's are algebraic integers, and (2) the w terms> are also algebraic integers.> Proving what, exactly, you ask?> #### Proving that the f = 3 case tells you NOTHING useful about the> necessary values of the w's. There is no unique way to write them> down. This is a special, exceptional case in which too many of the> of the f terms can be factored out.It is correct that they are indeterminate,and that's a VERY good pointthat you brought up.But now tell me, do you *still* believe the w's are then functions ofm?That is, once you divide off 3, it's gone, and the w's don't vary withm, so you can't claim m=0 is a special case where the w's arefunctions of m.Or do you think you still can?>But before at m=0, they were coprime to f, now they are not when f=3,>as they are constant. Clearly, they are constant in both cases with>respect to m, without regard to the value of f. Which makes sense as>f^2 is not a function of m, and it is what is being divided off.>> But in this case you can divide off *another* factor of f,> and that is what leads to the nonuniqueness shown above, which> wrecks your argument. This does not happen when f is a prime > bigger than 3 and m is coprime to f. f = 3 is a special case > of no interest or relevance to your main argument. It is a > nuisance distraction. It proves nothing.Really? Your position is that the w's are *functions* of m, but nowyou yourself bring out that with f=3, there's no way to determinetheir values, or do you claim there is?If you were correct, then even with f=3, the w's would STILL vary withm, so that m=0 would be a *special* case, and then they'd vary as mvaried.Are you claiming they do? >That is, if they were functions of m, so that w_1 w_2 = 1 at m=0 as a>*function* of m, then it wouldn't matter if f had a factor of 3 or>not, you'd STILL get w_1 w_2 = 1 at m=0, without regard to the value>of f.>But in fact, if f=3, you have w_1 w_2 = 3^{2/3} at m=0, which only>works if the w's are independent of m, which they are.>> See above. In the special case with f = 3, the w's> are not uniquely determined. You cannot draw conclusions> from it about how the f terms are distributed among > the w's or the linear factors. This case is a red > herring, and it is of no interest in your general > argument, where you require that f is a prime > 3. Worst> of all, it does not imply what you want.You seem to be very determined to convince yourself that themathematics says one thing, when it does not.It's *your* position that the w's are functions of m, so that you canclaim that m=0 is a special case.You need that claim so that you can then claim that the w's havevarying factors of f, as m varies.Now you need the w's to vary when the polynomial has a factor of 3,when f=3, but that's not a lot different from what was there beforewhen the factor was f^2.But here you try to dismiss one constant factor--3--as a unimportant,but try to hang on to f^2 which is also a constant factor with respectto m.Doesn't that bother you just a little bit?Does it seem rational to you? >It makes sense that they are anyway, as f^2 isn't a function of > m, but>I've seen that for some people the idea can take hold after seeing m=0>highlighted.>But if the w's were functions of m, then w_1 w_2 would equal 1,>without regard to the value of f, but it does not.> w1 = w2 = 1 and w3 = 3 is just one of the infinite range> of possibilities. It is Example 1 above.Well then, what makes you think the w's are *functions* of m, so thatm=0 would be a special case?Where's the mathematical logic in your thinking?Therefore, the factorization is>> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - >> 3(-1+mf^2 )x u^2 + u^3 f =>> (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>where you'll notice that the b's are algebraic integers with m=1,>f=sqrt(2), but that's a special case as generally they are not, which>shows a problem with the ring of algebraic integers.>> In this special case, P(x) does not even have> rational coefficients. It too is of no interest> or value for your main argument.Hmmm...that's a fascinating attempt at dodging the relevantmathematics.As I pointed out in another thread, with m=1, f=sqrt(2), y=uf, you get 2x^3 - 3xy^2 + y^3which is reducible as it factors as 2x^2 - 3xy^2 + y^3 = (x-y)(2x^2 + 2xy - y^2)and yes it is true that since y=uf, where f=sqrt(2), the y's areirrational, but it doesn't change the fact that the polynomial isreducible.Now that makes the *second* time I've pointed that out to you.Possibly you try to dismiss it because now using m=1(mod sqrt(2))destroys your claim that reducibility matters, as for instance,m=3=1(mod sqrt(2)) but now the resulting polynomial is *irreducible*and your claims, where you believe the w's are functions of m, wouldforce factors of f to shift.>And here I've packed in a lot of information as well.>> Not enough, clearly.Not if you refuse to follow mathematical logic.I think you've shown through your posting behavior that you areEXTREMELY dedicated to the notion that I'm wrong, but the problem isthat the mathematical logic is against you.So far, you've decided to go with your beliefs against the math.>First, with f coprime to 3, I now know that the factorization is>> P(m)/f^2 = (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>as the w's are constant with respect to m, so I can just check at m=0,>which revealed that w_1 w_2 = 1. Now that doesn't necessarily force>w_1 and w_2 to each equal 1, but even if they were factors of 1, i.e.>unit factors, that would only change b_1 and b_2.>>So I have my factorization without regard to m in terms of where the fgoes, and then I point out that you can actually check my work using>m=1, f=sqrt(2), as then you get a polynomial which you can factor>rather simply. So you can actually get the values for the b's and>check them, and see that they are all algebraic integers, and all are>coprime to 2.>However, usually, for f values that are coprime to 3, you don't get>b's that are algebraic integers, which shows a problem with the ring>of algebraic integers.>> Wrong! You *can* get algebraic integers, but *** not with> the properties you want ***, and there is no problem with> the ring of algebraic integers. Here is how things work when> f = 5, m = 1, u = 1, v = -1 + m*f^2, and> P(x) = (v^3 + 1)*x^3 - 3*v*x*(u*f)^2 + (u*f)^3:> P(x)/f^2 = P(x)/25 = 553*x^3 - 72*x + 5.> By the Magidin-McKinnon theorem (essentially proved earlier by > someone else [P. M. Cohn?]), this can be factored in the form> 553*x^3 - 72*x + 5 = (b1*x + w1)*(b2*x + w2)*(b3*x + w3),> where b1, b2, b3, and w1, w2, w3 are algebraic integers. > You can show using elementary Galois theory that EACH of> w1, w2, and w3 is not coprime to f = 5. Thus: a factorization of the desired form DOES exist, but it> does NOT have one of the properties that you desperately want.> No problem with the ring of algebraic integers, and no valid> proof for you. You lose on two counts. Too bad!And your *belief* depends on the w's being functions of m, which isnonsensical, as follows from your own statements, like where younoticed that with f=3, the w's are indeterminate, as 3 can divide offan infinite number of ways.Yet now here you are claiming that the w's are functions of m.That is NOT following the math. >Now the nice thing about a mathematical proof is that if someone>disagrees they have to find some misstep.> See above at #### ! The misstep in the current argument has been > found. No, but you have shown your own bias and refusal to followmathematical logic. >Unfortunately, people can *say* that proof is not a proof, even when>it is, just like if you tried to say you were human, and not a dog,someone might dispute any proof you might give, claiming it false.>> In this case, you have tried to use an irrelevant > red-herring argument to show what you want. Unfortunately,> in the special case you selected, the number f (= 3) does> factors *** non-uniquely *** through the linear terms of your> polynomial factorization, and you end up being able to> conclude:> *** N O T H I N G ***> about the cases in which you are interested.> But you have made progress. Do you realize how long it> took us to get through to you that there is actually a> nontrivial problem with generalizing from m = 0 to> m <> 0 ? Do you realize how many incorrect arguments> you have already burned through (including the present> one) in trying to handle that problem? Do you realize> that all of this is a waste of time, because your > main claims have already been shown to be false and> cannot be fixed by twiddling with the details?> Nora B.And readers should note that Nora Baron here arrogant and presumablyconfident, is still fighting to claim that f^2 divides off of apolynomial as a function of m, though it is itself constant withregard to m, when the poster has spent a lot of effort trying to claimthat 3 divides off in an inconsequential way, when f=3.The point is that the poster Nora Baron is not making sense.James Harris === > A mathematical proof begins with a truth, and proceeds by logical> steps to a conclusion which then must be true.> I've pulled a detailed exposition of a short argument that quickly> shows a problem with algebraic integers. It starts after the> reference.> Now here's a math proof. Those who doubt that fact can believe it's a> claim of proof, but it's verified to be a proof by tracing the> argument out.> In this case, I begin with an expression. The expression exists, so> that is the truth from which you start.> Consider, in the ring of algebraic integers,> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f).> That is, I have the identity which defines P(m) in terms of various> symbols, and it's all in the ring of algebraic integers, which means> that the symbols can only represent numbers that are algebraic> integers.> Now using b_1, b_2, b_3, w_1, w_2, and w_3, I have the factorization> P(m)/f^2 = (b_1 x + u w_1)(b_2 x + u w_2)(b_3 x + u w_3)James,You sometimes get into an argument as to whether something is afunction of something else. It might help if you made it clear at thebeginning that P is a function of f, m, u and x. And that the b_i andw_i are functions of f and m. You might then be able to show,subsequently, that something that looked at though it depended onsomething else, in fact does not.For instance:Let f, m, u and x be algebraic integers.Consider the function:P(f,m,u,x)=f^2((m^3 f^4 - 3m^2 f^2 + 3m)x^3 - 3(-1+mf^2)x u^2 + u^3 f)Since the set of algebraic integers is an integral domain, P(f,m,u,x)is necessarily an algebraic integer.Aside: Is P(f,m,u,x)/f^2 necessarily an algebraic integer?It is possible to find functions (of f and m) b_1, b_2, b_3, w_1, w_2,and w_3 such thatP(f,m,u,x)/f^2 =(b_1(f,m) x + u w_1(f,m))*(b_2(f,m) x + u w_2(f,m))*(b_3(f,m) x + u w_3(f,m))Clearly these functions are not uniquely determined.Aside: Can the functions b_1, b_2, b_3, w_1, w_2, and w_3 all bechosen such that, if f and m are algebraic integers, b_1(f,m) b_2(f,m)b_3(f,m) w_1(f,m) w_2(f,m) and w_3(f,m) are all algebraic integers?If m=0, we haveP(f,0,u,x)/f^2 =(b_1(f,0) x + u w_1(f,0))*(b_2(f,0) x + u w_2(f,0))*(b_3(f,0) x + u w_3(f,0))etcMath Fan === >A mathematical proof begins with a truth, and proceeds by logical>steps to a conclusion which then must be true.>I've pulled a detailed exposition of a short argument that quickly>shows a problem with algebraic integers. It starts after the>reference.Now here's a math proof. Those who doubt that fact can believe it's aclaim of proof, but it's verified to be a proof by tracing the>argument out.>> Not! See below.> I've clipped sections where there was no claim of error by the poster> Nora Baron.> You also clipped parts where I made valid claims that disagreewith your conclusions. I hope you will read ALL of this post, andread it carefully. > Essentially objections to how f^2 divides off now come down to>claiming that the w's are functions of m, but consider that w_1 w_2 =>1, when m=0, if f is coprime to 3.>>Now I'm focusing on what has been revealed to be an area of confusion.> Apparently some people believe that when I divide off f^2 that it can>divide off as a *function* of m, so that m=0 might be a special case. >I'm now starting the argument to address that belief by noting again>that w_1 w_2 = 1, when m=0, if f is coprime to 3. That is, when f>doesn't have 3 as a factor.>>But that was an arbitrary choice, so let f=3.>> f = 3 is irrelevant to what you want. There is> no reason to consider it. As you will see below, it> is a red herring and it does not show what you want.> Which would imply that you are claiming that there is a misstep.> However, f=3 shows that the w_1 w_2 = 3^{2/3} for ALL m, when f=3.> The expression you are working with is P(x)/f^2. What I showed in my post is that w1*w2 can be ANY two algebraic integerfactors of f = 3. It is NOT necessarily the case that w1*w2 = 3^{2/3}in that case. The case f = 3 does not give you any information aboutthe w's. What I have said is that in general, the factorization (including thevalues of the w's) is dependent on the value of m. That statementis correct when it is restricted to the cases of interest to you:the polynomial P(x) is irreducible and primitive. These conditionswill hold when f is a prime > 3 and m is coprime to f. They doNOT hold when f = 3 (P(x) is not primitive). The conditions are not artificial or arbitrary. I apply a theoremfrom algebraic number theory which requires irreducibility and(as noted by Arturo Magidin) primitivity. These conditions alsohappen to prevail in all the cases of interest to you: f prime > 3and m coprime to f. I do NOT make statements about theform of the factorization when f = 3, and certainly not whenm = 0. > However, w_1 w_2 is coprime to 3 when f is coprime to 3, at m=0.> Therefore, the w's are not functions of m, and in fact w_1 w_2 is> coprime to f, for all m, and m=0 is not a special case.> No. In all the cases of interest, the w's ARE dependent on m. If the w's are not dependent on m, then they must be constant.Right? As you have noted, when m = 0, you get P(0)/f^2 = w1*w2*u^2*(b3*x + u*w3)[1] = u^2*(b3*w1*w2*x + u*f). Right?But P(0)/f^2 also equals (you note) P(0)/f^2 = 3x*u^2 + u^3*f[2] = u^2*(3*x + u*f). Right?And looking at [1] and [2], you conclude w1*w2 = 1. Right?And that happens to be true regardless of the value of f. Right?*Including* f = 3.Now you say w1 and w2 do not depend on m. To me, thatwould mean that they are constant with respect to m. Right?But now when f = 3 and m <> 0, you say you have w1*w2 = 3^{2/3}.And when f = 3 and m = 0, from the above, you have w1*w2 = 1.You call that constant? You call that not dependent on m?[The fact is, when m = 0 and f = 3, the w's are indeterminateas discussed below.]> That is the conclusion that follows logically.> Well having read down, the poster does have a point which in fact is> that the 3's divide off in an indeterminate way, so it's not so easy> to just say that w_1 w_2 = 3^{2/3} because that could be the case, but> then again, maybe only w_3 has a factor of 3, so w_1 w_2 could still> be coprime to 3.> Aha. So you did get the point. Yay!>That is, I *said* f is coprime to 3 but in considering thispossibility it's worth it to relax that restriction and now consider>what would happen if it equals 3.>>Now w_1 w_2 = 3^{2/3} WITHOUT REGARD TO m. >>Seeing that is as simple as looking at>> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - >> 3(-1+mf^2 )x u^2 + u^3 f>with f=3 as then you have>> P(m)/3^2 = (m^3 3^4 - 3m^2 3^2 + 3m) x^3 - >> 3(-1+m3^2 )x u^2 + 3u^3>so *every* coefficient has a factor that is 3, as you can tell by>looking.>> Let's look at this in detail when m = 1 and u = 1. Then> P(m)/3^2 = (81 - 27 + 3)*x^3 - 3*8*x + 3 > = 3*(19*x^3 - 8*x + 1).> Ok.So with>> P(m)/3^2 = (b_1 x + u w_1)(b_2 x + u w_2)(b_3 x + u w_3)>>each of the b's and each of the w's has a factor that is 3^{1/3},>while the b's can have additional factors in common with 3, the w's>cannot, as when 3 is separated out, notice you have>> P(m)/3^2 = 3((m^3 3^3 - 3m^2 3 + m) x^3 - >> (-1+m3^2 )x u^2 + u^3).>> As above when m = 1, u = 1, this is> 3*(19*x^3 - 8*x + 1).> The polynomial inside the parentheses can be factored> in the form> [1] (19*x^3 - 8*x + 1) = (b1*x + 1)*(b2*x + 1)*(b3*x + 1),> where b1, b2, and b3 are the negatives of the roots> of the associated polynomial> u^3 + 8*u^2 - 19.> Since the roots of the latter polynomial are algebraic> integers, one concludes b1, b2, and b3 are algebraic > integers also. Now: how might you distribute the 3 in the expression 3*(b1*x + 1)*(b2*x + 1)*(b3*x + 1) ?> Answer: LOTS of ways! There is no unique way. Here are> several:> 1. (b1*x + 1)*(b2*x + 1)*(3*b3*x + 3)> 2. (sqrt(3)*b1*x + sqrt(3))*(sqrt(3)*b2*x + sqrt(3)*(b3*x + 1)> 3. (3^{1/3}*b1*x + 3^{1/3})*(3^{2/3}*b2*x + 3^{2/3})*(b3*x + 1) 4. (3^{1/5}*b1*x + 3^{1/5})*(3^{3/5}*b2*x + 3^{3/5})> *(3^{1/5}*b3*x + 3{1/5})> In fact INFINITELY many ways. Any way you want to split 3 as a> product of three numbers gives a factorization. And in all the> examples just given (and in infinitely many others) note that (1) the> coefficients of the x's are algebraic integers, and (2) the w terms> are also algebraic integers.> Proving what, exactly, you ask?> #### Proving that the f = 3 case tells you NOTHING useful about the> necessary values of the w's. There is no unique way to write them> down. This is a special, exceptional case in which too many of the> of the f terms can be factored out.> It is correct that they are indeterminate,and that's a VERY good point> that you brought up.> But now tell me, do you *still* believe the w's are then functions of> m?> I believe they are dependent on m when you restrict to the cases that happen to be of interest to you: f a prime > 3, m relatively prime to f. my point of view, these conditions (f = prime > 3, m coprime to f) are quitenatural also. I base my conclusions on a theorem in algebraic number theory which requires primitivity and irreducibility of a polynomial. When f = 3, you do not get primitivity and irreducibility. So indeed, in this special case, I do not pretend to say anything about the w's.> That is, once you divide off 3, it's gone, and the w's don't vary with> m, so you can't claim m=0 is a special case where the w's are> functions of m.> You have already divided off f^2. In this special case you candivide off another f. However, your factorization statement wasabout P(m)/f^2, not P(m)/f^3. If you want to consider thelatter, then you get w1 = w2 = w3 = 1, since the polynomialis then 19*x^3 - 8*x + 1.So I don't think you want to go there, eh?> Or do you think you still can?But before at m=0, they were coprime to f, now they are not when f=3,>as they are constant. Clearly, they are constant in both cases with>respect to m, without regard to the value of f. Which makes sense as>f^2 is not a function of m, and it is what is being divided off.>> But in this case you can divide off *another* factor of f,> and that is what leads to the nonuniqueness shown above, which> wrecks your argument. This does not happen when f is a prime bigger than 3 and m is coprime to f. f = 3 is a special case > of no interest or relevance to your main argument. It is a > nuisance distraction. It proves nothing.> Really? Your position is that the w's are *functions* of m, My position is that they are dependent on m, which is notquite the same as being functions of m. And in any case,my proofs regarding the factorization do not include thespecial cases f = 3 or m = 0. That does not mean myproofs are incorrect. It does mean that your entire discussionof f = 3 is irrelevant.> but now> you yourself bring out that with f=3, there's no way to determine> their values, or do you claim there is?> I certainly don't. You however did. You said the values wereindependent of m, i.e., constant, and you used the case f = 3to show it. But when f = 3, far from being a constant, they cannoteven be determined at all. They can be anything that divides 3.> If you were correct, then even with f=3, the w's would STILL vary with> m, so that m=0 would be a *special* case, and then they'd vary as m> varied.> Are you claiming they do?> Yes, when f is a prime > 3 and m is coprime to f. Whichhappens to be exactly the conditions that you want to consider also in your proof.That is, if they were functions of m, so that w_1 w_2 = 1 at m=0 as a>*function* of m, then it wouldn't matter if f had a factor of 3 or>not, you'd STILL get w_1 w_2 = 1 at m=0, without regard to the value>of f.>>But in fact, if f=3, you have w_1 w_2 = 3^{2/3} at m=0, which only>works if the w's are independent of m, which they are.>> See above. In the special case with f = 3, the w's> are not uniquely determined. You cannot draw conclusions> from it about how the f terms are distributed among > the w's or the linear factors. This case is a red > herring, and it is of no interest in your general > argument, where you require that f is a prime > 3. Worst> of all, it does not imply what you want.> You seem to be very determined to convince yourself that the> mathematics says one thing, when it does not.> Not at all! You have noted that I am right about the indeterminacy of the w's when f = 3. You were using thatcase in an attempt to prove that w1 and w2 are constantwith respect to m. I merely noted that in fact that case doesn't give you any information at all regarding the w's.In that case, the w's are indeterminate. Your conclusionwas not justified. It seems to me that it is YOU, not I,who is determined to convince yourself that the mathsays one thing, when in this case it doesn't actually sayanything. I thought it was a little bit of a subtle point. Clearly youhad not considered it previously, and clearly from whatyou have said here, you understand it. This in itself is thus a rather rare event. It wrecks this particular part of your argument. That is the point. > It's *your* position that the w's are functions of m, so that you can> claim that m=0 is a special case.> Dependent on m, not necessarily functions of m. And I canclaim it only when f = prime > 3 and m is coprime to f. Butthat is a very big set of values, and is plenty good enough for both our purposes.> You need that claim so that you can then claim that the w's have> varying factors of f, as m varies.> Now you need the w's to vary when the polynomial has a factor of 3,> when f=3, No, I don't care what happens in that special case. I don't claimthat my proofs hold in that case. The polynomial in question isnot irreducible and primitive.> but that's not a lot different from what was there before> when the factor was f^2.> When f is prime > 3, it is a LOT different.> But here you try to dismiss one constant factor--3--as a unimportant,> but try to hang on to f^2 which is also a constant factor with respect> to m.> It's not that it is unimportant (though in fact it is - the case f = 3is of no interest to you in your arguments either). It is that I don'tmake any claims about what happens when f = 3. The theorem that I use in that case does not apply anyway.> Doesn't that bother you just a little bit?> Nope.> Does it seem rational to you?> Yes. What seems irrational to me is to claim that when f = 3, w1*w2 = 3^{2/3}, when in fact w1 andw2 are, as you yourself have noted above, indeterminatewhen f = 3. The f = 3 case adds no information to yourknowledge of the relationship between m and w1 and w2.You claimed that it confirmed that w1 and w2 were constant.It did no such thing.>It makes sense that they are anyway, as f^2 isn't a function of > m, but>I've seen that for some people the idea can take hold after seeing m=0>highlighted.>But if the w's were functions of m, then w_1 w_2 would equal 1,>without regard to the value of f, but it does not.>> w1 = w2 = 1 and w3 = 3 is just one of the infinite range> of possibilities. It is Example 1 above.> Well then, what makes you think the w's are *functions* of m, so that> m=0 would be a special case?> Where's the mathematical logic in your thinking?> See above. Unlike you, I do not make claims aboutthe special case f = 3. I say that when f = prime > 3 andm is coprime to f, the w's are dependent on m. Proveme wrong in THAT case and I will start to take notice.Therefore, the factorization is>> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - >> 3(-1+mf^2 )x u^2 + u^3 f => (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>where you'll notice that the b's are algebraic integers with m=1,f=sqrt(2), but that's a special case as generally they are not, which>shows a problem with the ring of algebraic integers.>> In this special case, P(x) does not even have> rational coefficients. It too is of no interest> or value for your main argument.> Hmmm...that's a fascinating attempt at dodging the relevant> mathematics.> This is 180 degrees wrong! The RELEVANT mathematics arenot when f = 3. The cases of interest to YOU are f = prime > 3,m coprime to f. Doesn't it seem a little odd for you to spend allthis effort in a subset where your own proofs are not concerned?> As I pointed out in another thread, with m=1, f=sqrt(2), y=uf, you get> 2x^3 - 3xy^2 + y^3> which is reducible as it factors as> 2x^2 - 3xy^2 + y^3 = (x-y)(2x^2 + 2xy - y^2)> and yes it is true that since y=uf, where f=sqrt(2), the y's are> irrational, but it doesn't change the fact that the polynomial is> reducible.> There are two things going on here. When you write 2*x^3 - 3*x*y^2 + y^3you are considering a polynomial in two variables. Indeedthat does factor in the obvious way. But when you subsitute y = sqrt(2), you are now considering a polynomial in ONE variable (x). You areback to the case in which you are interested. But thispolynomial in ONE variable has a constant term whichis irrational. You know perfectly well that it does notfactor with rational coefficients. In your factorizations, you are invariably factoring apolynomial in one indeterminate, x. That is why you consider linear factors of the form (b1*x + u*f), etc.. It is from that point of view that you should be consideringyour polynomial, not as a polynomial in two variables.> Now that makes the *second* time I've pointed that out to you.> Right, thanks. But sqrt(2) is still irrational, eh? Or did that change recently in Georgia?> Possibly you try to dismiss it because now using m=1(mod sqrt(2))> destroys your claim that reducibility matters, as for instance,> m=3=1(mod sqrt(2)) but now the resulting polynomial is *irreducible*> and your claims, where you believe the w's are functions of m, would> force factors of f to shift.> You have lost me here. Are you saying that two values of mthat agree mod sqrt(2) are necessarily actually the same?>And here I've packed in a lot of information as well.>> Not enough, clearly.> Not if you refuse to follow mathematical logic.> I think you've shown through your posting behavior that you are> EXTREMELY dedicated to the notion that I'm wrong, but the problem is> that the mathematical logic is against you.> You are correct that I think you are wrong. Saying I am dedicated to that notion is not different from saying I am dedicatedto defending what I believe to be true. Is that a character flaw inyour eyes? Should I not do that?> So far, you've decided to go with your beliefs against the math.> My beliefs are based entirely on the math and nothing elsein this discussion.>First, with f coprime to 3, I now know that the factorization is>> P(m)/f^2 = (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>as the w's are constant with respect to m, so I can just check at m=0,>which revealed that w_1 w_2 = 1. Now that doesn't necessarily force>w_1 and w_2 to each equal 1, but even if they were factors of 1, i.e.>unit factors, that would only change b_1 and b_2.>>So I have my factorization without regard to m in terms of where the f>goes, and then I point out that you can actually check my work using>m=1, f=sqrt(2), as then you get a polynomial which you can factorrather simply. So you can actually get the values for the b's and>check them, and see that they are all algebraic integers, and all are>coprime to 2.>>However, usually, for f values that are coprime to 3, you don't getb's that are algebraic integers, which shows a problem with the ring>of algebraic integers.>> Wrong! You *can* get algebraic integers, but *** not with> the properties you want ***, and there is no problem with> the ring of algebraic integers. Here is how things work when> f = 5, m = 1, u = 1, v = -1 + m*f^2, and> P(x) = (v^3 + 1)*x^3 - 3*v*x*(u*f)^2 + (u*f)^3:> P(x)/f^2 = P(x)/25 = 553*x^3 - 72*x + 5.> By the Magidin-McKinnon theorem (essentially proved earlier by > someone else [P. M. Cohn?]), this can be factored in the form> 553*x^3 - 72*x + 5 = (b1*x + w1)*(b2*x + w2)*(b3*x + w3),> where b1, b2, b3, and w1, w2, w3 are algebraic integers. > You can show using elementary Galois theory that EACH of> w1, w2, and w3 is not coprime to f = 5. > Thus: a factorization of the desired form DOES exist, but it> does NOT have one of the properties that you desperately want.> No problem with the ring of algebraic integers, and no valid> proof for you. You lose on two counts. Too bad!> And your *belief* depends on the w's being functions of m, which is> nonsensical, as follows from your own statements, like where you> noticed that with f=3, the w's are indeterminate, as 3 can divide off> an infinite number of ways.> It's amazing how you got this turned around. You claimed thatthe case f = 3 showed that the w's were constant. In fact in thecase f = 3, the w's are indeterminate. It clear from what you justsaid that you actually understand this. The case f = 3 added nothing to your knowledge of the behavior of the w's. Yet you claim that *** I *** am being nonsensical !!! Incredible!> Yet now here you are claiming that the w's are functions of m.> I claim that the w's are dependent on m under the conditionsthat f = prime > 3, and m coprime to f. What you have donenot only does not support your own conclusions in the specialno-interest case where f = 3, it doesn't even touch the caseswhich are of genuine interest to both of us.> That is NOT following the math.> Exactly the opposite is true.>Now the nice thing about a mathematical proof is that if someone>disagrees they have to find some misstep.>> See above at #### ! The misstep in the current argument has been > found.> No, but you have shown your own bias and refusal to follow> mathematical logic.> Really, there was nothing in my post but mathematical logic.Sorry it didn't support your beliefs.>Unfortunately, people can *say* that proof is not a proof, even when>it is, just like if you tried to say you were human, and not a dog,>someone might dispute any proof you might give, claiming it false.>> In this case, you have tried to use an irrelevant > red-herring argument to show what you want. Unfortunately,> in the special case you selected, the number f (= 3) does> factors *** non-uniquely *** through the linear terms of your> polynomial factorization, and you end up being able to> conclude:> *** N O T H I N G ***> about the cases in which you are interested. But you have made progress. Do you realize how long it> took us to get through to you that there is actually a> nontrivial problem with generalizing from m = 0 to> m <> 0 ? Do you realize how many incorrect arguments> you have already burned through (including the present> one) in trying to handle that problem? Do you realize> that all of this is a waste of time, because your > main claims have already been shown to be false and> cannot be fixed by twiddling with the details?> Nora B.> And readers should note that Nora Baron here arrogant and presumably> confident, is still fighting to claim that f^2 divides off of a> polynomial as a function of m, though it is itself constant with> regard to m, when the poster has spent a lot of effort trying to claim> that 3 divides off in an inconsequential way, when f=3.> Well, duh. Yes, that is what I was saying. I agree that I spent alot of time on an inconsequential case. I was simply trying to showthat your conclusions *even in that case* were not justified. At leastyou got the point this time, so I don't think it was a complete waste.> The point is that the poster Nora Baron is not making sense.> It's clear from what you have said here that you understood what I wassaying, and even, I daresay, that you were surprised by it. So clearly, it is not that what I said did not make sense. It is that you did not like the conclusion. Nora B. > James Harris === A mathematical proof begins with a truth, and proceeds by logical>steps to a conclusion which then must be true.>I've pulled a detailed exposition of a short argument that quickly>shows a problem with algebraic integers. It starts after the>reference. >Now here's a math proof. Those who doubt that fact can believe it's a>claim of proof, but it's verified to be a proof by tracing the>argument out.>> Not! See below.> I've clipped sections where there was no claim of error by the poster> Nora Baron.> You also clipped parts where I made valid claims that disagree> with your conclusions. I hope you will read ALL of this post, and> read it carefully. I read all of the previous post. If you feel something material wasclipped you should have said what, rather than use an insinuation. > Essentially objections to how f^2 divides off now come down to>claiming that the w's are functions of m, but consider that w_1 w_2 =>1, when m=0, if f is coprime to 3.>>Now I'm focusing on what has been revealed to be an area of confusion.> Apparently some people believe that when I divide off f^2 that it can>divide off as a *function* of m, so that m=0 might be a special case. >I'm now starting the argument to address that belief by noting again>that w_1 w_2 = 1, when m=0, if f is coprime to 3. That is, when f>doesn't have 3 as a factor.>But that was an arbitrary choice, so let f=3.> f = 3 is irrelevant to what you want. There is> no reason to consider it. As you will see below, it> is a red herring and it does not show what you want.> Which would imply that you are claiming that there is a misstep. However, f=3 shows that the w_1 w_2 = 3^{2/3} for ALL m, when f=3.>> The expression you are working with is> P(x)/f^2.> What I showed in my post is that w1*w2 can be ANY two algebraic integer> factors of f = 3. It is NOT necessarily the case that w1*w2 = 3^{2/3}> in that case. The case f = 3 does not give you any information about> the w's.Well it turns out I was in error as the answer is given by consideringthe factorization P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)as with f=3, it's clear that *each* has 3 as a factor, which gives you P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - (-1+m 3^2 )x u^2 + u^3 = (a_1/3 x + u)(a_2/3 x + u)(a_3/3 x + u).Now using the b's and w's gives P(m)/3^2 = 3((m^3 3^3 - 3^2 m^2 + m) x^3 - (-1+m 3^2 )x u^2 + u^3) = (b_1 x + u w_1)(b_2 x + u w_2)(b_3 x + u w_3)but at m=0, I have P(0)/3^2 = u^2(3x - 3u) = u^2(b_3 w_1 w_2 - 3u), soand dividing off the last 3 gives P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - (-1+m 3^2 )x u^2 + u^3 = (b_1 x + u)(b_2 x + u)(b_3/3 x + u)so it's NOT true that it's completely arbitrary what the w's are.Notice that using m=0 and the constant term P(0) forces the case, asthe only thing that can vary is the indices as my choices there werearbitrary. > What I have said is that in general, the factorization (including the> values of the w's) is dependent on the value of m. That statement> is correct when it is restricted to the cases of interest to you:> the polynomial P(x) is irreducible and primitive. These conditions> will hold when f is a prime > 3 and m is coprime to f. They do> NOT hold when f = 3 (P(x) is not primitive). You're saying that equations *check* to see if P(x) is irreducibleover rationals, which you claim happens if f is a prime greater than 3and m is coprime to f.A function is a function. It doesn't check coprimeness of somevariable to figure out if it's a function.> The conditions are not artificial or arbitrary. I apply a theorem> from algebraic number theory which requires irreducibility and> (as noted by Arturo Magidin) primitivity. These conditions also> happen to prevail in all the cases of interest to you: f prime > 3> and m coprime to f. I do NOT make statements about the> form of the factorization when f = 3, and certainly not when> m = 0. It's *algebra* so you can use f and if there are functions of m,then they will be functions of m, whether f is coprime to 3 or not.> However, w_1 w_2 is coprime to 3 when f is coprime to 3, at m=0.> Therefore, the w's are not functions of m, and in fact w_1 w_2 is> coprime to f, for all m, and m=0 is not a special case.> No. In all the cases of interest, the w's ARE dependent on m.That is wrong as I've shown with P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - (-1+m 3^2 )x u^2 + u^3 = (a_1/3 x + u)(a_2/3 x + u)(a_3/3 x + u)as a 3 must divide off through *each* of the a's.Your claims would require that the a's have a factor of f that variesas a function of m, except you wish to dodge your assertion herebecause f=3, and make claims that would force equations to *choose* tobe functions or constants with regard to m based on whether or not fis coprime to 3.> If the w's are not dependent on m, then they must be constant.> Right? They are. > As you have noted, when m = 0, you get> P(0)/f^2 = w1*w2*u^2*(b3*x + u*w3)> [1] = u^2*(b3*w1*w2*x + u*f). Right?Yup.> But P(0)/f^2 also equals (you note)> P(0)/f^2 = 3x*u^2 + u^3*f> [2] = u^2*(3*x + u*f). Right?> And looking at [1] and [2], you conclude w1*w2 = 1. Right?Yup.> And that happens to be true regardless of the value of f. Right?> *Including* f = 3.Yup.> Now you say w1 and w2 do not depend on m. To me, that> would mean that they are constant with respect to m. Right?> But now when f = 3 and m <> 0, you say you have w1*w2 = 3^{2/3}.That was a mistake. Now if you were following the math, then youwould simply note it as a mistake, but instead you're trying to use*my* mistake to convince that something else that is not true, istrue. > And when f = 3 and m = 0, from the above, you have w1*w2 = 1.> You call that constant? You call that not dependent on m?I call my statements where I said w_1 w_2 = 3^{2/3} mistaken.> [The fact is, when m = 0 and f = 3, the w's are indeterminate> as discussed below.]I did believe that myself for a while, which is why I posted whatfollows, later I realized it didn't follow mathematically.> That is the conclusion that follows logically.> Well having read down, the poster does have a point which in fact is> that the 3's divide off in an indeterminate way, so it's not so easy> to just say that w_1 w_2 = 3^{2/3} because that could be the case, but> then again, maybe only w_3 has a factor of 3, so w_1 w_2 could still> be coprime to 3.> Aha. So you did get the point. Yay!Well yes, I did understand what you thought was an issue, and at firstblush agreed that in fact the w's are indeterminate when f=3.> In fact INFINITELY many ways. Any way you want to split 3 as a> product of three numbers gives a factorization. And in all the> examples just given (and in infinitely many others) note that (1) the coefficients of the x's are algebraic integers, and (2) the w terms> are also algebraic integers.> Proving what, exactly, you ask?> #### Proving that the f = 3 case tells you NOTHING useful about the> necessary values of the w's. There is no unique way to write them> down. This is a special, exceptional case in which too many of the> of the f terms can be factored out. It is correct that they are indeterminate,and that's a VERY good point> that you brought up.> It is a very important point, but I made a mistake saying they areindeterminate, but I'm glad you brought up the issue.In fact, your *same* points would actually apply in general with P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf),where just like before with 3, you now have f^2 as a factor.Do you see that now?You might want to avoid seeing it now as you went to so much effort totry and show that f=3 makes a special case, but can you see it now?> But now tell me, do you *still* believe the w's are then functions of> m?> I believe they are dependent on m when you restrict to the cases > that happen to be of interest to you: f a prime > 3, m relatively prime to f. > my point of view, these conditions (f = prime > 3, m coprime to f) are quite> natural also. I base my conclusions on a theorem in algebraic number theory > which requires primitivity and irreducibility of a polynomial. > When f = 3, you do not get primitivity and irreducibility. So indeed, in > this special case, I do not pretend to say anything about the w's. Well forget about the w's for now, and look at P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)and consider that you're now trying to say that f divides off as somekind of function, as long as f is coprime to 3.Doesn't that bother you just a *little* bit, as it goes against theobjections you yourself raised with f=3?> That is, once you divide off 3, it's gone, and the w's don't vary with> m, so you can't claim m=0 is a special case where the w's are> functions of m.> You have already divided off f^2. In this special case you can> divide off another f. However, your factorization statement was> about P(m)/f^2, not P(m)/f^3. If you want to consider the> latter, then you get w1 = w2 = w3 = 1, since the polynomial> is then> 19*x^3 - 8*x + 1.> So I don't think you want to go there, eh? Why not? > Or do you think you still can?>But before at m=0, they were coprime to f, now they are not when f=3,>as they are constant. Clearly, they are constant in both cases with>respect to m, without regard to the value of f. Which makes sense asf^2 is not a function of m, and it is what is being divided off.>> But in this case you can divide off *another* factor of f,> and that is what leads to the nonuniqueness shown above, which> wrecks your argument. This does not happen when f is a prime > bigger than 3 and m is coprime to f. f = 3 is a special case > of no interest or relevance to your main argument. It is a > nuisance distraction. It proves nothing.> Really? Your position is that the w's are *functions* of m, > My position is that they are dependent on m, which is not> quite the same as being functions of m. And in any case,> my proofs regarding the factorization do not include the> special cases f = 3 or m = 0. That does not mean my> proofs are incorrect. It does mean that your entire discussion> of f = 3 is irrelevant.Now you've been trying to say that m=0, is a special case, if f=3, sothat you can claim that certain variables have different factors of f,depending on m, but now you're saying it's not quite the same as thembeing functions of m?Why don't you try and explain that mathematically?And as for f=3 being irrelevant, how is f then relevant with P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)?Your *own* objections would indicate that you must believe that how fdivides off is actually *indeterminate*, which I can then show to bewrong, as I have by noting that with f=3, an f has to divide off from*each* of the a's.Do you think maybe you've been trying to make something simple *more*complicated in order to hold a pet belief, against mathematical logic?If you do not believe so, please explain carefully why *you* think f^2divides off in some determined way here, after arguing in another casethat f, when it equaled 3, did not, to the extent that you now calldiscussion of it irrelevant.> but now> you yourself bring out that with f=3, there's no way to determine> their values, or do you claim there is? I certainly don't. You however did. You said the values were> independent of m, i.e., constant, and you used the case f = 3> to show it. But when f = 3, far from being a constant, they cannot> even be determined at all. They can be anything that divides 3. I made two errors. First I *said* that w_1 w_2 = 3^{2/3}, when f=3,which has been shown to be an error. You, however, claimed they wereindeterminate, and I agreed with you, which was a second error.Now you're holding on to your own error, which would actually shootdown your other objections anyway, as f=3 can't be distinguished inthe way you wish, as all that changes is that instead of just f^2dividing off, f^3 divides off of P(m), where P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf).Now trapped by mathematical logic, you are squirming trying to findsome way to hold on to your pet beliefs, against the math.> If you were correct, then even with f=3, the w's would STILL vary with> m, so that m=0 would be a *special* case, and then they'd vary as m> varied.> Are you claiming they do?> Yes, when f is a prime > 3 and m is coprime to f. Which> happens to be exactly the conditions that you want to > consider also in your proof.Apparently you have your heart set on my claims being wrong, but whythink of them as my claims? It's mathematics.Mathematics isn't true in order to upset you.It's just true.Now then, can you see that you have no basis for your opinion that f^2divides off in certain ways, just because f is coprime to 3, when youyourself have challenged that position when f=3?Why do you wish to believe that f^2 or f^3 when f=3, divides off ofP(m) as a variable dependent on m?Isn't it true that you have beliefs you're trying to protect?But it's *mathematics*, so why would you want to hold on to beliefsthat are wrong? After all, in math, you don't have to *protect* beliefs, asmathematical logic is there for you. It doesn't need your help.>That is, if they were functions of m, so that w_1 w_2 = 1 at m=0 as a*function* of m, then it wouldn't matter if f had a factor of 3 or>not, you'd STILL get w_1 w_2 = 1 at m=0, without regard to the value>of f.>>But in fact, if f=3, you have w_1 w_2 = 3^{2/3} at m=0, which only>works if the w's are independent of m, which they are.> See above. In the special case with f = 3, the w's> are not uniquely determined. You cannot draw conclusions> from it about how the f terms are distributed among > the w's or the linear factors. This case is a red > herring, and it is of no interest in your general > argument, where you require that f is a prime > 3. Worst> of all, it does not imply what you want.> You seem to be very determined to convince yourself that the> mathematics says one thing, when it does not.> Not at all! You have noted that I am right about the > indeterminacy of the w's when f = 3. You were using that> case in an attempt to prove that w1 and w2 are constant> with respect to m. I merely noted that in fact that case > doesn't give you any information at all regarding the w's.> In that case, the w's are indeterminate. Your conclusion> was not justified. It seems to me that it is YOU, not I,> who is determined to convince yourself that the math> says one thing, when in this case it doesn't actually say> anything.Well the evidence is to the contrary as I'm flexible.I've learned that it's useless to fight the math.So I made a mistake about the w's. I make mistakes. But at least Icould entertain the possibility.You however seem set on a certain belief and damn mathematical logic. > I thought it was a little bit of a subtle point. Clearly you> had not considered it previously, and clearly from what> you have said here, you understand it. This in itself is thus > a rather rare event.And here you are being insulting. Why do you think correctmathematics needs defense?Mathematics is not a child that can be harmed.If you are right, then I assure you that if you make a logical case,beginning with a truth and proceeding by logical steps to aconclusion, then that conclusion is true.> It wrecks this particular part of your argument. That is the point.That may be your point, but your emotional needs do not affect thetruth or falsity of a mathematical argument.The math argument just does not care.> It's *your* position that the w's are functions of m, so that you can> claim that m=0 is a special case.> Dependent on m, not necessarily functions of m. And I can> claim it only when f = prime > 3 and m is coprime to f. But> that is a very big set of values, and is plenty good enough for > both our purposes.However that goes against the facts. The fact is that P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)and if f=3, you get *each* of the a's having a factor of 3, for ALL m,without regard to its value.Do you understand?Now then, your attempt at distinguishing f=3 from f coprime to 3, inorder to force a functional dependency falls flat at that point.So what happens when f is coprime to 3?Then f^2 divides off through only two of the a's as I've shown.It's that mathematical result which you are fighting with such energyand emotion.You're fighting the math, not me.> You need that claim so that you can then claim that the w's have varying factors of f, as m varies.> Now you need the w's to vary when the polynomial has a factor of 3,> when f=3, > No, I don't care what happens in that special case. I don't claim> that my proofs hold in that case. The polynomial in question is> not irreducible and primitive.For readers what the poster Nora Baron is talking about here isreducibility over rationals otherwise known as reducibility over Q.For an example, consider P(x)= x^2 + 2x + 1 = (x+1)(x+1), as apolynomial reducible over Q, whereas P(x) = x^2 + 5x + 2, is anexample of a polynomial irreducible over Q.The position Nora Baron is fighting for, is the claim that dependingon whether or not you can reduce a polynomial over rationals, it willfactor in certain ways, to where if it is irreducible, ALL of itsroots MUST not be coprime to any prime INTEGER factor of its constantterm.So by the poster's beliefs now because x^2 + 5x + 2 is irreducibleover rationals, both its roots must have some non unit factor incommon with 2 based on that irreducibility alone.> but that's not a lot different from what was there before> when the factor was f^2.> When f is prime > 3, it is a LOT different.> But here you try to dismiss one constant factor--3--as a unimportant,> but try to hang on to f^2 which is also a constant factor with respect> to m.> It's not that it is unimportant (though in fact it is - the case f = 3> is of no interest to you in your arguments either). It is that I don't> make any claims about what happens when f = 3. The > theorem that I use in that case does not apply anyway.Hmmm...if that's correct, then how would it apply to P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f)?On what basis have you been arguing then?> Doesn't that bother you just a little bit?> Nope.That is you feel confident you are right, despite logicalinconsistencies in your position?> Does it seem rational to you?> Yes. > What seems irrational to me is to claim that > when f = 3, w1*w2 = 3^{2/3}, when in fact w1 and> w2 are, as you yourself have noted above, indeterminate> when f = 3. The f = 3 case adds no information to your> knowledge of the relationship between m and w1 and w2.> You claimed that it confirmed that w1 and w2 were constant.> It did no such thing.I made a mistake. It's that simple.Yup, I was saying w_1 w_2 = 3^{2/3} and that was wrong, which issomething that can be worked out mathematically.I'm glad you caught that mistake as I was posting it all over theplace!There is an answer, which is found by following the math. >It makes sense that they are anyway, as f^2 isn't a function of > m, but>I've seen that for some people the idea can take hold after seeing m=0>highlighted.>But if the w's were functions of m, then w_1 w_2 would equal 1,>without regard to the value of f, but it does not.>> w1 = w2 = 1 and w3 = 3 is just one of the infinite range> of possibilities. It is Example 1 above.> Well then, what makes you think the w's are *functions* of m, so that> m=0 would be a special case? Where's the mathematical logic in your thinking?> See above. Unlike you, I do not make claims about> the special case f = 3. I say that when f = prime > 3 and> m is coprime to f, the w's are dependent on m. Prove> me wrong in THAT case and I will start to take notice.Ok, so now f=3 is a special case. Before it was m=0 as your specialcase and now f=3 is one as well.It looks to me that when the math shows your beliefs to be wrong, youfind a way to call it a special case!Therefore, the factorization is>> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - >> 3(-1+mf^2 )x u^2 + u^3 f =>> (b_1 x + u)(b_2 x + u)(b_3 x + uf)>where you'll notice that the b's are algebraic integers with m=1,>f=sqrt(2), but that's a special case as generally they are not, which>shows a problem with the ring of algebraic integers.>> In this special case, P(x) does not even have> rational coefficients. It too is of no interest> or value for your main argument.> Hmmm...that's a fascinating attempt at dodging the relevant> mathematics.> This is 180 degrees wrong! The RELEVANT mathematics are> not when f = 3. The cases of interest to YOU are f = prime > 3,> m coprime to f. Doesn't it seem a little odd for you to spend all> this effort in a subset where your own proofs are not concerned?I go where necessity and the mathematical logic lead.Here I'm working to refute your popular position that reducibilityover Q actually forces factors to move around in a factorization,which depends on claims that require that f^2, constant with regard tom, and a factor of P(m) divides off from P(m) as a variable dependenton m.I've determined that I can destroy your case using f=3, which is whatI'm doing.> As I pointed out in another thread, with m=1, f=sqrt(2), y=uf, you get> 2x^3 - 3xy^2 + y^3> which is reducible as it factors as> 2x^2 - 3xy^2 + y^3 = (x-y)(2x^2 + 2xy - y^2)> and yes it is true that since y=uf, where f=sqrt(2), the y's are> irrational, but it doesn't change the fact that the polynomial is> reducible.> There are two things going on here. When you write> 2*x^3 - 3*x*y^2 + y^3> you are considering a polynomial in two variables. Indeed> that does factor in the obvious way.> But when you subsitute y = sqrt(2), you are now > considering a polynomial in ONE variable (x). You are> back to the case in which you are interested. But this> polynomial in ONE variable has a constant term which> is irrational. You know perfectly well that it does not> factor with rational coefficients. > In your factorizations, you are invariably factoring a> polynomial in one indeterminate, x. That is why you > consider linear factors of the form (b1*x + u*f), etc.. > It is from that point of view that you should be considering> your polynomial, not as a polynomial in two variables.What you said is not true. In fact, the factorizations I show arethose like P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)which is in more than one variable.I can *relate* such factorizations to simpler polynomials, where youand others have argued.I find it interesting that you continue to defend your claims about 2x^2 - 3xy^2 + y^3 = (x-y)(2x^2 + 2xy - y^2)as you demonstrate a troubling inflexibility.Well possibly it's because you realize that then I can use m=1(modsqrt(2)) to destroy your claims. > Now that makes the *second* time I've pointed that out to you. Right, thanks. But sqrt(2) is still irrational, eh? Or did > that change recently in Georgia?That's what's grand about mathematics, it's not particular to anyplace or time.It seems to me that you demonstrate belief in something other thanmathematics. > Possibly you try to dismiss it because now using m=1(mod sqrt(2))> destroys your claim that reducibility matters, as for instance,> m=3=1(mod sqrt(2)) but now the resulting polynomial is *irreducible*> and your claims, where you believe the w's are functions of m, would> force factors of f to shift.> You have lost me here. Are you saying that two values of m> that agree mod sqrt(2) are necessarily actually the same?Your claim is to how factors in common with f will distribute withinthe factorization where you have called m=0 a special case.But with f=sqrt(2), m=1, I can demonstrate another case.You've tried to challenge that because f=sqrt(2), and others mightclaim that maybe m=1 is a special case, so I've pointed out that usingm=1(mod sqrt(2)) destroys your claims as then factors of f are fixed.Think about it like this, if f=sqrt(2), then I can take the m=1 case,and use m=1(mod sqrt(2)) to make factors of 2 stay in their place.Do you understand?>And here I've packed in a lot of information as well.>> Not enough, clearly.> Not if you refuse to follow mathematical logic.> I think you've shown through your posting behavior that you are> EXTREMELY dedicated to the notion that I'm wrong, but the problem is> that the mathematical logic is against you.>> You are correct that I think you are wrong. Saying I am > dedicated to that notion is not different from saying I am dedicated> to defending what I believe to be true. Is that a character flaw in> your eyes? Should I not do that?You can believe any number of things, even when they're false.But in mathematics, you are supposed to adjust your beliefs ifnecessary to the math.Your beliefs are NOT more important than mathematical truth.Can you understand?> So far, you've decided to go with your beliefs against the math.> My beliefs are based entirely on the math and nothing else> in this discussion.I've proven that statement false.>First, with f coprime to 3, I now know that the factorization is>> P(m)/f^2 = (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>as the w's are constant with respect to m, so I can just check at m=0,which revealed that w_1 w_2 = 1. Now that doesn't necessarily force>w_1 and w_2 to each equal 1, but even if they were factors of 1, i.e.>unit factors, that would only change b_1 and b_2.>>So I have my factorization without regard to m in terms of where the f>goes, and then I point out that you can actually check my work using>m=1, f=sqrt(2), as then you get a polynomial which you can factorrather simply. So you can actually get the values for the b's and>check them, and see that they are all algebraic integers, and all are>coprime to 2.>However, usually, for f values that are coprime to 3, you don't get>b's that are algebraic integers, which shows a problem with the ring>of algebraic integers.> Wrong! You *can* get algebraic integers, but *** not with> the properties you want ***, and there is no problem with> the ring of algebraic integers. Here is how things work when> f = 5, m = 1, u = 1, v = -1 + m*f^2, and P(x) = (v^3 + 1)*x^3 - 3*v*x*(u*f)^2 + (u*f)^3: P(x)/f^2 = P(x)/25 = 553*x^3 - 72*x + 5.> By the Magidin-McKinnon theorem (essentially proved earlier by someone else [P. M. Cohn?]), this can be factored in the form> 553*x^3 - 72*x + 5 = (b1*x + w1)*(b2*x + w2)*(b3*x + w3),> where b1, b2, b3, and w1, w2, w3 are algebraic integers. > You can show using elementary Galois theory that EACH of> w1, w2, and w3 is not coprime to f = 5. > Thus: a factorization of the desired form DOES exist, but it> does NOT have one of the properties that you desperately want.> No problem with the ring of algebraic integers, and no valid> proof for you. You lose on two counts. Too bad!> And your *belief* depends on the w's being functions of m, which is> nonsensical, as follows from your own statements, like where you> noticed that with f=3, the w's are indeterminate, as 3 can divide off> an infinite number of ways.> It's amazing how you got this turned around. You claimed that> the case f = 3 showed that the w's were constant. In fact in the> case f = 3, the w's are indeterminate. It clear from what you just> said that you actually understand this. The case f = 3 added > nothing to your knowledge of the behavior of the w's. Yet you > claim that *** I *** am being nonsensical !!! Incredible!I was convinced by you that the w's are indeterminate, after I had thewrong position that w_1 w_2 = 3^{2/3}, and later found out you werewrong by checking the mathematical logic.In your world, do people never change their minds?If you are someone who refuses to change their minds then that mightexplain things. > Yet now here you are claiming that the w's are functions of m.> I claim that the w's are dependent on m under the conditions> that f = prime > 3, and m coprime to f. What you have done> not only does not support your own conclusions in the special> no-interest case where f = 3, it doesn't even touch the cases> which are of genuine interest to both of us.Here you've declared that f=3 is a special no-interest case whichgoes against the math.> That is NOT following the math.> Exactly the opposite is true.Then prove it, mathematically.Don't *claim* one thing and do another.Prove your claims.>Now the nice thing about a mathematical proof is that if someone>disagrees they have to find some misstep.>> See above at #### ! The misstep in the current argument has been > found. No, but you have shown your own bias and refusal to follow> mathematical logic.> Really, there was nothing in my post but mathematical logic.> Sorry it didn't support your beliefs.Then discussions should be quick.You show the logical chain in your reasoning and that will be it.Show the mathematical logic that you believe supports your position,if you can.>Unfortunately, people can *say* that proof is not a proof, even when>it is, just like if you tried to say you were human, and not a dog,>someone might dispute any proof you might give, claiming it false.>> In this case, you have tried to use an irrelevant > red-herring argument to show what you want. Unfortunately, in the special case you selected, the number f (= 3) does factors *** non-uniquely *** through the linear terms of your> polynomial factorization, and you end up being able to> conclude:> *** N O T H I N G ***> about the cases in which you are interested.> But you have made progress. Do you realize how long it> took us to get through to you that there is actually a> nontrivial problem with generalizing from m = 0 to> m <> 0 ? Do you realize how many incorrect arguments> you have already burned through (including the present> one) in trying to handle that problem? Do you realize> that all of this is a waste of time, because your > main claims have already been shown to be false and> cannot be fixed by twiddling with the details?> Nora B.> And readers should note that Nora Baron here arrogant and presumably> confident, is still fighting to claim that f^2 divides off of a> polynomial as a function of m, though it is itself constant with> regard to m, when the poster has spent a lot of effort trying to claim> that 3 divides off in an inconsequential way, when f=3.>> Well, duh. Yes, that is what I was saying. I agree that I spent a> lot of time on an inconsequential case. I was simply trying to show> that your conclusions *even in that case* were not justified. At least> you got the point this time, so I don't think it was a complete waste.However, the arguments you used would destroy your own claims aboutf^2 dividing off from P(m) in some particular way.So you're trapped both by what you said, and by the mathematicallogic.You can, of course, restate your position, if you wish.> The point is that the poster Nora Baron is not making sense.>> It's clear from what you have said here that you understood what I was> saying, and even, I daresay, that you were surprised by it. So clearly, > it is not that what I said did not make sense. It is that you did not > like the conclusion.> Nora B. That is not correct. I *accepted* your conclusion and then found outthat it was false, when I checked the math.Now you have the option to follow the math, or stick with falsebeliefs.James Harris === >[...]>>Well it turns out I was in error [...]>That was a mistake. [...]>>It is a very important point, but I made a mistake [...]>>Apparently you have your heart set on my claims being wrong, but why>think of them as my claims? It's mathematics.************************David C. Ullrich === [.snip.]>>Essentially objections to how f^2 divides off now come down to>>claiming that the w's are functions of m, but consider that w_1 w_2 =>>1, when m=0, if f is coprime to 3.>>Now I'm focusing on what has been revealed to be an area of confusion.>> Apparently some people believe that when I divide off f^2 that it can>>divide off as a *function* of m, so that m=0 might be a special case. >>I'm now starting the argument to address that belief by noting again>>that w_1 w_2 = 1, when m=0, if f is coprime to 3. That is, when f>>doesn't have 3 as a factor.>>But that was an arbitrary choice, so let f=3.>> f = 3 is irrelevant to what you want. There is>no reason to consider it. As you will see below, it>is a red herring and it does not show what you want.I have not been following all the details of James's most recentpresentation. But it ->seems<- to me that he is falling back to an oldmistake yet again.It is of course true that any polynomial identity will become a truestatement about specific numbers when evaluated (to be more precise,if you have an identity in the polynomial ring R[x], where R is acommutative ring, then under the evaluation homomorphism x|->a it willyield a true statement in R, for any a in R). However, it is not thecase that any identity obtained under evaluation can be lifted to apolynomial identity.Here James develops certain formulas in general; he is being sloppy,in so far as he is not being careful to remain in his polynomial ring,not all terms that appear lie there. It so happens that when aparticular evaluation is made, certain identities hold, and Jamestries to deduce that these are polynomial identities. That's why whenconfronted, he always falls back on claiming that sincex^2+2x+1=(x+1)^2, then this holds for any value of x. I.e., he isaffirming the consequent. === === 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 figures few readers can critize. A great many people are staggered to this extend, that they imagine there must be the indefinite 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 === > [.snip.]>>Essentially objections to how f^2 divides off now come down to>>claiming that the w's are functions of m, but consider that w_1 w_2 =>>1, when m=0, if f is coprime to 3.>>Now I'm focusing on what has been revealed to be an area of confusion.>> Apparently some people believe that when I divide off f^2 that it can>>divide off as a *function* of m, so that m=0 might be a special case. >>I'm now starting the argument to address that belief by noting again>>that w_1 w_2 = 1, when m=0, if f is coprime to 3. That is, when f>>doesn't have 3 as a factor.>>But that was an arbitrary choice, so let f=3.>> f = 3 is irrelevant to what you want. There is>no reason to consider it. As you will see below, it>is a red herring and it does not show what you want.> I have not been following all the details of James's most recent> presentation. But it ->seems<- to me that he is falling back to an old> mistake yet again.What I've seen is that Arturo Magidin engages in making posts whichapparently are meant to persuade. My interest is in what the actualmathematical truth is, though it is of secondary interest that Iconvince others.For Arturo Magidin, it appears that persuasion is the primaryinterest, which can be seen from his comments in contrast with thefacts which I present below. > It is of course true that any polynomial identity will become a true> statement about specific numbers when evaluated (to be more precise,> if you have an identity in the polynomial ring R[x], where R is a> commutative ring, then under the evaluation homomorphism x|->a it will> yield a true statement in R, for any a in R). However, it is not the> case that any identity obtained under evaluation can be lifted to a> polynomial identity.> Here James develops certain formulas in general; he is being sloppy,> in so far as he is not being careful to remain in his polynomial ring,> not all terms that appear lie there. It so happens that when a> particular evaluation is made, certain identities hold, and James> tries to deduce that these are polynomial identities. That's why when> confronted, he always falls back on claiming that since> x^2+2x+1=(x+1)^2, then this holds for any value of x. I.e., he is> affirming the consequent.What I've noticed is that Arturo Magidin works VERY hard to bebelieved.authoritative or looks mathematical, but he rarely actually provesanything relevant to his central objections.Here the pertinent expression, which he doesn't even bother to givehaving deleted it out of the post to which he is replying, is P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f).Notice the factor f^2, which is, of course, constant with regard to m,but Arturo Magidin and his diligent supporters try to argue that thef^2 divides off dependent on m, so that they can challenge that withthe factorization P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)f^2 divides off through only two of the a's, which is a result thatcan be looked at with m=1, f=sqrt(2), as then you have P(m) = 2x^3 -3xy^2 + y^3, using y=sqrt(2)u,and that factors as P(m) = (x-y)(2x^2 + 2xy - 1).However, Arturo Magidin and his supporters try to ignore that case,while continuing to claim that m=0 is a special case.Their focus on m=0 comes from the fact that P(0)/f^2 = u^2(3x + uf)which I use to show how f^2 divides off from P(m).Usually the claim by Arturo Magidin and others like him who disputehow f^2 divides off, trying to claim it divides off as a factor of m,is to say that the reducibilty over *rationals* of f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f)considered to be a polynomial with respect to x, determines how f^2divides off from the expression.What I've found is that despite repeated demonstrations to thecontrary posters like Arturo Magidin refuse to back down, but insteadengage in various tactics to convince people that they are right.James Harris === > What I've found is that despite repeated demonstrations to the> contrary posters like Arturo Magidin refuse to back down, but instead> engage in various tactics to convince people that they are right.>> James HarrisInteresting. Contrast this with:What I've found is that despite repeated demonstrations to the contrary James Harris refuses to back down, but instead engages in various tactics to convince people that he is right.Be assured that the vast majority (if not all) of the readers of thesenewsgroups, believe the second of these statements is true. Arturo (andmany other talented people) have given you way more time than you deserve.Back in 1973 when I was an undergraduate studying group theory, I stumbledonto a paradoxical result. I spent the better part of a weekend going overmy logic and could not find a mistake, so when Monday rolled around, I wentto my professor's office and asked him to look over my work, He immediatelysaw that I had to be wrong, and after a bit, explained that I was making abad assumption at one point. I do not recall the details, because this wasso long ago, but the gist of it was that I was making a mistake aboutproperties of a group due to my lack of knowledge and experience. I trustedmy teacher, and devoted myself to bettering my understanding of somefundamentals. A month or so later I reviewed my work and with theimproved state of my knowledge, could clearly see my errors. See thedifference? I didn't see a conspiracy to deny my results, but recognizedthat my knowledge was deficient, and I corrected that.James, you use invalid terminology, you continue to use a colloquial ratherthan a formal exposition, you skip important steps (my high school algebrateacher made that issue very clear to me...), you repeatedly useintermediate results that are not proven. You have been given excellentfeedback from some very knowledgeable people - the basic gist of which is:get yourself some education in fundamentals. Nobody is going to take youseriously if it's obvious you haven't been doing your homework... === >A mathematical proof begins with a truth, and proceeds by logicalsteps to a conclusion which then must be true.>I've pulled a detailed exposition of a short argument that quickly>shows a problem with algebraic integers. It starts after the>reference. >Now here's a math proof. Those who doubt that fact can believe it's a>claim of proof, but it's verified to be a proof by tracing the>argument out.> Not! See below.> I've clipped sections where there was no claim of error by the poster> Nora Baron.> You also clipped parts where I made valid claims that disagree> with your conclusions. I hope you will read ALL of this post, and> read it carefully. > I read all of the previous post. If you feel something material was> clipped you should have said what, rather than use an insinuation.> >Essentially objections to how f^2 divides off now come down toclaiming that the w's are functions of m, but consider that w_1 w_2 =>1, when m=0, if f is coprime to 3.>Now I'm focusing on what has been revealed to be an area of confusion.> Apparently some people believe that when I divide off f^2 that it can>divide off as a *function* of m, so that m=0 might be a special case. I'm now starting the argument to address that belief by noting again>that w_1 w_2 = 1, when m=0, if f is coprime to 3. That is, when f>doesn't have 3 as a factor.>>But that was an arbitrary choice, so let f=3.>> f = 3 is irrelevant to what you want. There is> no reason to consider it. As you will see below, it> is a red herring and it does not show what you want.> Which would imply that you are claiming that there is a misstep.> However, f=3 shows that the w_1 w_2 = 3^{2/3} for ALL m, when f=3.> The expression you are working with is> P(x)/f^2. What I showed in my post is that w1*w2 can be ANY two algebraic integer> factors of f = 3. It is NOT necessarily the case that w1*w2 = 3^{2/3}> in that case. The case f = 3 does not give you any information about> the w's.> Well it turns out I was in error ... not for the first time, or, I suspect, the last.as the answer is given by considering> the factorization> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)> as with f=3, it's clear that *each* each what?> has 3 as a factor, which gives you> P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - > (-1+m 3^2 )x u^2 + u^3 = > (a_1/3 x + u)(a_2/3 x + u)(a_3/3 x + u).> What I showed in my previous post implies that ifa1, a2, and a3 are the negatives of the roots of the polynomial u^3 - 8*u^2 - 19,then a perfectly legit factorization is:[****] (a1*x + 1)*(a2*x + 1)*(27*a3*x + 27)which happens to equal 27*(a1*x + 1)*(a2*x + 1)*(a3*x + 1).I think you can work out the reasoningfor yourself on that. If not, let me know.> Now using the b's and w's gives> P(m)/3^2 = 3((m^3 3^3 - 3^2 m^2 + m) x^3 - > (-1+m 3^2 )x u^2 + u^3) = > (b_1 x + u w_1)(b_2 x + u w_2)(b_3 x + u w_3)> but at m=0, I have> P(0)/3^2 = u^2(3x - 3u) = u^2(b_3 w_1 w_2 - 3u), so> and dividing off the last 3 gives> P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - > (-1+m 3^2 )x u^2 + u^3 = > (b_1 x + u)(b_2 x + u)(b_3/3 x + u)> Nope, this is NOT OK. Why? Because you are assuming what you want to prove. You want to show that thefactorization when m <> 0 is similar to that when m = 0.Here m = 3. In case you have not noticed, 3 is not equalto 0. Plus, if you look at what I said above at [****}, you will see a counterexample. Thus I guess there is no point in going through the rest of whatyou have here. I will do so anyway just to be fair.> so it's NOT true that it's completely arbitrary what the w's are.> Notice that using m=0 and the constant term P(0) forces the case, as> the only thing that can vary is the indices as my choices there were> arbitrary.> No, sorry. You are using what you want to prove. This techniquecould simplify a great many difficult proofs, but it is notconsidered a fair tactic in mathematics. In politics, possibly. > What I have said is that in general, the factorization (including the> values of the w's) is dependent on the value of m. That statement> is correct when it is restricted to the cases of interest to you:> the polynomial P(x) is irreducible and primitive. These conditions> will hold when f is a prime > 3 and m is coprime to f. They do> NOT hold when f = 3 (P(x) is not primitive). You're saying that equations *check* to see if P(x) is irreducible> over rationals, which you claim happens if f is a prime greater than 3> and m is coprime to f.> I am of course not saying any such thing. Equations don't check anything.Your putting it in that way is an attempt to deny the conclusionwithout doing any hard mathematics. Trying to pretend that my argumentrequires that equations are intelligent beings or whatever is silly, andyou know damn well it is not mathematics. In your typical equation, P(x) = (v^3 + 1)*x^x - 3*v*x*(u*f)^2 + (u*f)^3,where v = -1 + m*f^2, note that the variable m occurs inboth the leading coefficient (hidden in v^3) and in themiddle coefficient (hidden in v itself). Certainly thereis no doubt that if you change m, you change the roots of the equation. Now if you factor the equation in theform (a1*x + c1)*(a2*x + c2)*(a3*x + c3),where a1, a2, a3, and c1, c2, c3 are algebraic integers,the roots are r1 = -c1/a1, r2 = -c2/a2, and r3 = -c3/a3.We have agreed here that a1, a2, and a3 are functionsof m. If the equation happens to be reducible intolinear terms with rational roots, then you can assumethat c1, c2, and c3 are ordinary integers, and that theyfactor the number (u*f)^3. In general you are not goingto be able to tell HOW they factor (u*f)^3. That willdepend on the MIDDLE term. Here are two quadratic examples that may clarifythis: x^2 - 7*x + 10 = (x - 2)*(x - 5). x^2 - 11*x + 10 = (x - 1)*(x - 10).Note that changing the MIDDLE term changed thefactors! In the first example, the roots followthe factorization 2*5 = 10. In the secondexample, the roots follow the factorization 1*10 = 10.The constant term, 10, stayed the same in both examples, just as, in the case in which youare interested, the term (u*f)^3 stays the same.Again: it was changing the MIDDLE term which resulted in different values of the roots anda different form of factorization.And AGAIN: in your polynomial, if you change m, you will change the coefficient of the MIDDLE term, -3*v*(u*f)^2.because you will have changed v.> A function is a function. It doesn't check coprimeness of some> variable to figure out if it's a function.> Silly. Are you saying that because functions cannot checkanything about their arguments, they must always be constantwith respect to those arguments ??? Again, THIS IS NOT MATHEMATICS. This is an attempt to ridicule my hard, rigorous mathematical conclusion by implyingthat I impute some kind of intelligence to functions, etc.. It doesn't wash. IT ISN'T A MATHEMATICAL ARGUMENT. I giveit no weight whatsoever, nor should anyone else.> The conditions are not artificial or arbitrary. I apply a theorem> from algebraic number theory which requires irreducibility and> (as noted by Arturo Magidin) primitivity. These conditions also> happen to prevail in all the cases of interest to you: f prime > 3> and m coprime to f. I do NOT make statements about the> form of the factorization when f = 3, and certainly not when> m = 0. > It's *algebra* so you can use f and if there are functions of m,> then they will be functions of m, whether f is coprime to 3 or not.> Nope. My examples showed very clearly that 3 is a special case.Plus I don't care about it anyway. And it is irrelevant for yourpurposes too.> However, w_1 w_2 is coprime to 3 when f is coprime to 3, at m=0.> Therefore, the w's are not functions of m, and in fact w_1 w_2 is> coprime to f, for all m, and m=0 is not a special case.>> No. In all the cases of interest, the w's ARE dependent on m.> That is wrong as I've shown with> P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - > (-1+m 3^2 )x u^2 + u^3 = > (a_1/3 x + u)(a_2/3 x + u)(a_3/3 x + u)> as a 3 must divide off through *each* of the a's.> Your argument is incorrect. You assumed what you wantedto prove. You generalized from m = 0 to m <> 0.> Your claims would require that the a's have a factor of f that varies> as a function of m, except you wish to dodge your assertion here> because f=3, and make claims that would force equations to *choose* to> be functions or constants with regard to m based on whether or not f> is coprime to 3.> Oh, bull. This constant stupid attempt to imply that I assume equations choose etc., is getting tiresome. PlusIT ISN'T MATHEMATICS. Here are two ways to state the situation: (1) The values of the w coefficients depend on the coefficients of the polynomial, which in turn depend on m. (2) The w's choose what their values are after they see what values m has. They are conscious beings who look around and make decisions about things that they see, and change their behavior accordingly. Which of those do you think more accurately representsmy position? Which is a (NON-MATHEMATICAL) attempt to ridicule it? Don't you think the default assumption would be (1) ?Don't you think the natural assumption would be to assume (1) until somebody proved otherwise? The ideathat elements of a factorization might be expected to depend on the coefficients of the polynomial, especially the MIDDLE coefficients, is not exactly rocket science, eh? > If the w's are not dependent on m, then they must be constant.> Right? > They are.> Not. Definitely not. And again, your attempt to proveotherwise has been shot down: in my previous post, byshowing that the case f = 3 leaves the w's entirelyindeterminate. And in the present post, by showing thatyou tried to assume what you wanted to prove.> As you have noted, when m = 0, you get P(0)/f^2 = w1*w2*u^2*(b3*x + u*w3)> [1] = u^2*(b3*w1*w2*x + u*f). Right?> Yup.> You know, always saying Yup instead of yes makes you soundlike a dimwitted yokel. You might consider varying itfrom time to time.> But P(0)/f^2 also equals (you note)> P(0)/f^2 = 3x*u^2 + u^3*f> [2] = u^2*(3*x + u*f). Right?> And looking at [1] and [2], you conclude w1*w2 = 1. Right?> Yup.> See above.> And that happens to be true regardless of the value of f. Right?> *Including* f = 3.> Yup.> And see above again, Abner.> Now you say w1 and w2 do not depend on m. To me, that> would mean that they are constant with respect to m. Right?> But now when f = 3 and m <> 0, you say you have w1*w2 = 3^{2/3}.> That was a mistake. Now if you were following the math, then you> would simply note it as a mistake, but instead you're trying to use> *my* mistake to convince that something else that is not true, is> true.> Now you are asking me to read your mind and correct your mistakes for you. That is too much. You make alot of mistakes. If they were just misprints I wouldnot mind, and I could probably figure out what you intended. But as in this case, they are far more thanmisprints. I had no idea what you intended. Youpresented it as part of a serious argument. All I couldtell was, it didn't make any sense. Also I pointed this out in one or more previous postswhich you must not have read, or read too quickly tounderstand. You kept repeating it. I note you havehad to retract it also in posts in other threads.Certainly not my fault!> And when f = 3 and m = 0, from the above, you have w1*w2 = 1.> You call that constant? You call that not dependent on m?> I call my statements where I said w_1 w_2 = 3^{2/3} mistaken.> [The fact is, when m = 0 and f = 3, the w's are indeterminate> as discussed below.]> I did believe that myself for a while, which is why I posted what> follows, later I realized it didn't follow mathematically.> In which case, I am VERY ANNOYED that you continue to actas if you are infallible, and frequently accuse the rest of us of lying. I could easily have said you were lying here, or trying to confuse people, or cover up the truth. That is what youhave done repeatedly EVEN WHEN I PRESENT CORRECT MATH. It is *not* what I did in your case. I assumed you had made a mistake of some kind, but I didn't know whether it was a superficial error, and you really had not noticed it, or what. But you seemed to be putting a lot of weighton it as justifying your side of the argument. I wasOBLIGATED to point out that it was wrong. The other thing that I must note here is, you oftenadmit *minor* mistakes like this with reasonable grace.In such cases our objections are easy to understand, andimpossible to deny. But when we present rigorous but deeper and more difficult objections - equally valid,in my view - you apparently refuse to even THINK aboutthem. Why? I think, because you don't know enoughmath to understand them. When I object to some statementof yours and I invoke, say, a simple theorem from Galois theory to show it is wrong, to ME it seems justas wrong as the little algebra mistake you made here.But you act as if my Galois theory argument cannot betrusted and that I must be lying. All you have to dois go learn a little Galois theory or algebraic numbertheory for yourself. This too you refuse to do. You recall my thread, Challenge of the Century ?I was (and am) pretty sure in that case that I wasright. Just as right as in the present little-algebra-mistake case. The only theory I used was an algebraicnumber theory theorem which you have seen before andactually accepted. Even so, I was taking a hugechance. I am not perfect. I make mistakes. I couldhave had an error in that post, and you could havepicked it up. Still could, for all I know. I was,however, extremely confident of my argument. No oneelse raised the slightest objection to it. I think it completely clinched the case againstyour proof in Advance Polynomial Factorization. So what happened? You totally ignored it as faras I can tell. The point? I have paid great attention to yourarguments. I have dug into them in great detail.I have presented proofs that in my view blast yourclaims out of the water. You have ignored them.You insist that we not only disprove your claims,but we must also (1) disprove them without usingany theory that you haven't bothered to learn, and(2) we must also find where your mistakes are thatled you to your erroneous claims. The latter is what the present thread is allabout. It shouldn't even be necessary. We arebeing MORE THAN FAIR to you. For most people,a rigorous disproof of their claims is enoughto send them scurrying back to the drawing board.For you, we have to (1) simplify our disproofs so that a child could understand them, and, toboot, (2) find exactly where the child screwedup, a task that should be left to the childhimself. The real point here: from my point of view,my big objections to your bogus math are justas valid as my little objections to simplealgebra errors. You should at least try tounderstand them. If you cannot refute them,it is just like refusing to acknowledge and change the kind of error you noted above. And finally: do NOT expect me to cut youany slack for making algebra mistakes. I honestly cannot read your mind.> That is the conclusion that follows logically.> Well having read down, the poster does have a point which in fact is> that the 3's divide off in an indeterminate way, so it's not so easy> to just say that w_1 w_2 = 3^{2/3} because that could be the case, but> then again, maybe only w_3 has a factor of 3, so w_1 w_2 could still> be coprime to 3.> Aha. So you did get the point. Yay!> Well yes, I did understand what you thought was an issue, and at first> blush agreed that in fact the w's are indeterminate when f=3.> And at second blush, you have tried to pull back again,*assuming the very thing you were trying to prove*. Note thateven in that case, you did not actually identify anything wrong with what I said. You went off on another (unjustified)tangent. > > In fact INFINITELY many ways. Any way you want to split 3 as a> product of three numbers gives a factorization. And in all the> examples just given (and in infinitely many others) note that (1) the> coefficients of the x's are algebraic integers, and (2) the w terms> are also algebraic integers.> Proving what, exactly, you ask? #### Proving that the f = 3 case tells you NOTHING useful about the> necessary values of the w's. There is no unique way to write them> down. This is a special, exceptional case in which too many of the> of the f terms can be factored out.> It is correct that they are indeterminate,and that's a VERY good point> that you brought up.> It is a very important point, but I made a mistake saying they are> indeterminate, but I'm glad you brought up the issue.> No, you were right the first time. There is absolutely nothing wrongwith my argument that they are indeterminate. How can youdeny explicit examples?> In fact, your *same* points would actually apply in general with P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf),> where just like before with 3, you now have f^2 as a factor.> No, I don't see that at all. In the case of f = 3,you know that another 3 factors out of the left side.In the case where f <> 3, that is not true. For example,when f = 5, m = 1, u = 1, you have P(x)/f^2 = 553*x^3 - 72*x + 5,and you cannot factor any more 5's through that polynomial:f^2 = 25 is the most you can do. Neither 553 nor 72 aredivisible by 5. > Do you see that now?> No. In the case where f = 3, again with m = 1 and u = 1, youhave P(x)/f^2 = 57*x^3 - 24*x + 3,and I CAN factor another 3 out of that. That makes an enormousdifference as my previous post showed.> You might want to avoid seeing it now as you went to so much effort to> try and show that f=3 makes a special case, but can you see it now?> See above. It looks to me like 3 divides 57 and 24, but 5does NOT divide 553 and 72. Cold, hard arithmetic.> But now tell me, do you *still* believe the w's are then functions of> m? I believe they are dependent on m when you restrict to the cases > that happen to be of interest to you: f a prime > 3, m relatively prime to f. > my point of view, these conditions (f = prime > 3, m coprime to f) are quite> natural also. I base my conclusions on a theorem in algebraic number theory > which requires primitivity and irreducibility of a polynomial. > When f = 3, you do not get primitivity and irreducibility. So indeed, in > this special case, I do not pretend to say anything about the w's.> Well forget about the w's for now, and look at> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)> and consider that you're now trying to say that f divides off as some> kind of function, as long as f is coprime to 3.> Doesn't that bother you just a *little* bit, as it goes against the> objections you yourself raised with f=3?> Actually, no. First of all, you are assuming without visiblejustification that the factorization is of the form (a1*x + uf)*(a2*x + uf)*(a3*x + uf),when you should be assuming it is (a1*x + c1)*(a2*x + c2)*(a3*x + c3),where, as guaranteed by the Magidin-McKinnon theorem, a1, a2, a3, and c1, c2, c3 are algebraic integers. TheM-M theorem does not guarantee more than that. Certainlyit does not guarantee that c1 = uf, c2 = uf, c3 = uf.What makes you think that ???> That is, once you divide off 3, it's gone, and the w's don't vary with> m, so you can't claim m=0 is a special case where the w's are> functions of m. You have already divided off f^2. In this special case you can> divide off another f. However, your factorization statement was> about P(m)/f^2, not P(m)/f^3. If you want to consider the> latter, then you get w1 = w2 = w3 = 1, since the polynomial> is then> 19*x^3 - 8*x + 1.> So I don't think you want to go there, eh?> Why not?> Because the constant term is 1, and IN THIS CASE, you CANassume that the factorization is of the form (a1*x + 1)*(a2*x + 1)*(a3*x + 1).[Would you like to see a proof of that? Probably not.]That is, the w's are all equal to 1. None are divisibleby any factor of 3. That too does is not in agreementwith your previous claims about the w's. > Or do you think you still can?>But before at m=0, they were coprime to f, now they are not when f=3,>as they are constant. Clearly, they are constant in both cases with>respect to m, without regard to the value of f. Which makes sense asf^2 is not a function of m, and it is what is being divided off.>> But in this case you can divide off *another* factor of f,> and that is what leads to the nonuniqueness shown above, which> wrecks your argument. This does not happen when f is a prime > bigger than 3 and m is coprime to f. f = 3 is a special case of no interest or relevance to your main argument. It is a > nuisance distraction. It proves nothing.> Really? Your position is that the w's are *functions* of m, My position is that they are dependent on m, which is not> quite the same as being functions of m. And in any case,> my proofs regarding the factorization do not include the> special cases f = 3 or m = 0. That does not mean my> proofs are incorrect. It does mean that your entire discussion> of f = 3 is irrelevant.> Now you've been trying to say that m=0, is a special case, if f=3, so> that you can claim that certain variables have different factors of f,> depending on m, but now you're saying it's not quite the same as them> being functions of m?> Dependent on m and functions of m are not the same.For example, suppose n depends on m in the sense that ifm is divisible by 13, n is an even integer. That does NOTmean that n is a function of m. It does mean that if m1and m2 are two different values for n, you do not expectthat the corresponding n's, n1 and n2, are necessarilythe same.> Why don't you try and explain that mathematically?> See above. > And as for f=3 being irrelevant, how is f then relevant with> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)?> Your *own* objections would indicate that you must believe that how f> divides off is actually *indeterminate*, which I can then show to be> wrong, as I have by noting that with f=3, an f has to divide off from> *each* of the a's.> First of all, as I noted above, when f<> 3, I do not agree that you can assume the factorization has the form (a1*x + uf)*(a2*x + uf)*(a3*x + uf),and I don't see why you assume that either. It is simplynot true in general, and it is not stated as a part ofthe Magidin-McKinnon theorem. Secondly, if here you are talking about f = 3, thenanother f DOES can be divided off, and it leads to nonuniqueb's and w's as I noted in my previous post. See my previous discussion of this also. My previous postshowing nonuniqueness still stands. You cannot deny explicit examples with bogus theory.> Do you think maybe you've been trying to make something simple *more*> complicated in order to hold a pet belief, against mathematical logic?> If you do not believe so, please explain carefully why *you* think f^2> divides off in some determined way here, after arguing in another case> that f, when it equaled 3, did not, to the extent that you now call> discussion of it irrelevant.> Jesus. See above. I have given more than ample explanations of this.*Read them*.> but now you yourself bring out that with f=3, there's no way to determine> their values, or do you claim there is? I certainly don't. You however did. You said the values were> independent of m, i.e., constant, and you used the case f = 3> to show it. But when f = 3, far from being a constant, they cannot> even be determined at all. They can be anything that divides 3.> I made two errors. First I *said* that w_1 w_2 = 3^{2/3}, when f=3,> which has been shown to be an error. You, however, claimed they were> indeterminate, and I agreed with you, which was a second error.> Plus in this post, you made the really egregious error oftrying to assume what you wanted to prove.> Now you're holding on to your own error, which would actually shoot> down your other objections anyway, as f=3 can't be distinguished in> the way you wish, as all that changes is that instead of just f^2> dividing off, f^3 divides off of P(m), where> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf).> See above.> Now trapped by math> If you were correct, then even with f=3, the w's would STILL vary with> m, so that m=0 would be a *special* case, and then they'd vary as m> varied.> Are you claiming they do?> Yes, when f is a prime > 3 and m is coprime to f. Which> happens to be exactly the conditions that you want to > consider also in your proof.> Apparently you have your heart set on my claims being wrong, but why> think of them as my claims? It's mathematics.> Has nothing to do with my heart. In various places, such asAPF, you claim certain things are true. They demonstrably are not. You think you have proved them. Clearly yourproof has an error. That is what we are talking abouthere.> Mathematics isn't true in order to upset you.> What ???> It's just true.> A tautology obviously. And implicitly, another claim thatyou yourself are infallible. You are really saying MYmathematics is invariably true. I cannot swallow that. By now a little humility should have crept in. You DOmake mistakes, after all. Until you find an errorin things like Challenge of the Century, I will haveto regard your claims as just that: claims.> Now then, can you see that you have no basis for your opinion that f^2> divides off in certain ways, just because f is coprime to 3, when you> yourself have challenged that position when f=3?> Why do you wish to believe that f^2 or f^3 when f=3, divides off of> P(m) as a variable dependent on m?> Isn't it true that you have beliefs you're trying to protect?> But it's *mathematics*, so why would you want to hold on to beliefs> that are wrong?> After all, in math, you don't have to *protect* beliefs, as> mathematical logic is there for you. It doesn't need your help.> See above. You are beating an extremely dead horse. It isbeginning to reek.That is, if they were functions of m, so that w_1 w_2 = 1 at m=0 as a>*function* of m, then it wouldn't matter if f had a factor of 3 or>not, you'd STILL get w_1 w_2 = 1 at m=0, without regard to the value>of f.>But in fact, if f=3, you have w_1 w_2 = 3^{2/3} at m=0, which only>works if the w's are independent of m, which they are.>> See above. In the special case with f = 3, the w's> are not uniquely determined. You cannot draw conclusions> from it about how the f terms are distributed among > the w's or the linear factors. This case is a red > herring, and it is of no interest in your general > argument, where you require that f is a prime > 3. Worst> of all, it does not imply what you want.> You seem to be very determined to convince yourself that the> mathematics says one thing, when it does not.> Not at all! You have noted that I am right about the > indeterminacy of the w's when f = 3. You were using that> case in an attempt to prove that w1 and w2 are constant> with respect to m. I merely noted that in fact that case > doesn't give you any information at all regarding the w's.> In that case, the w's are indeterminate. Your conclusion> was not justified. It seems to me that it is YOU, not I,> who is determined to convince yourself that the math> says one thing, when in this case it doesn't actually say> anything.> Well the evidence is to the contrary as I'm flexible.> I've learned that it's useless to fight the math.> I see little evidence of such learning.> So I made a mistake about the w's. I make mistakes. But at least I> could entertain the possibility.> You however seem set on a certain belief and damn mathematical logic.> On the contrary. That damned mathematical logic is theonly reason I have for what I think. > I thought it was a little bit of a subtle point. Clearly you> had not considered it previously, and clearly from what> you have said here, you understand it. This in itself is thus > a rather rare event. And here you are being insulting. I apologize. However I have seen worse.> Why do you think correct> mathematics needs defense?> I would be the last to think that. Incorrect mathematics, on the other hand, needs to beattacked!> Mathematics is not a child that can be harmed.> You come up with the most bizarre statements. In onebreath, you say you make mistakes. In the next breath,you are implying that what you have done is *unassailable*.Incredible !!! Plus you imply I am a would-be child-beater!> If you are right, then I assure you that if you make a logical case,> beginning with a truth and proceeding by logical steps to a> conclusion, then that conclusion is true.> Good. Glad we agree on that. In view of that, why don'tyou have a look at the argument in Challenge of the Century,and tell me which step is not logical ?> It wrecks this particular part of your argument. That is the point.> That may be your point, but your emotional needs do not affect the> truth or falsity of a mathematical argument.> Forget my emotional needs. You have nothing to do with them and don't know what they are.> The math argument just does not care.> Ah, yes. You falsely ridicule my argument on the grounds that I must believe the w's act like littlepeople, making decisions about how they factor depending on the value of m, etc.. And now YOUseem to somehow have inside information on theemotional state of the math. Are you familiar with the word hubris ?If not, are you familiar with the word irony ?> It's *your* position that the w's are functions of m, so that you can> claim that m=0 is a special case. Dependent on m, not necessarily functions of m. And I can> claim it only when f = prime > 3 and m is coprime to f. But> that is a very big set of values, and is plenty good enough for > both our purposes.> However that goes against the facts. The fact is that> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)> and if f=3, you get *each* of the a's having a factor of 3, for ALL m,> without regard to its value.> No, little man. My previous post showed very clearly, veryexplicitly, the contrary. A possible factorization could be (b1*x + 1)*(b2*x + 1)*(27*b3*x + 27),where b1, b2, and b3 are the negatives of the roots of u^3 - 8*u^2 - 19.Your blather above does not change the fact that*such examples exist*.> Do you understand?> Assuredly. See just above.> Now then, your attempt at distinguishing f=3 from f coprime to 3, in> order to force a functional dependency falls flat at that point.> On the contrary. Your attempt to show that the w's areconstant on the basis of what happens when f = 3 is whatfalls flat. See above.> So what happens when f is coprime to 3?> Then f^2 divides off through only two of the a's as I've shown.> When f <> 3, you cannot assume the factorization takes theform (a1*x + uf)*(a2*x + uf)*(a3*x + uf). The most you can say is that it can be factored as (a1*x + c1)*(a2*x + c2)*(a3*x + c3).> It's that mathematical result which you are fighting with such energy> and emotion.> Oh please. > You're fighting the math, not me.> Again, you are 180 degrees off. The math is my friend.> You need that claim so that you can then claim that the w's have> varying factors of f, as m varies.> Now you need the w's to vary when the polynomial has a factor of 3,> when f=3, > No, I don't care what happens in that special case. I don't claim> that my proofs hold in that case. The polynomial in question is> not irreducible and primitive.> For readers what the poster Nora Baron is talking about here is> reducibility over rationals otherwise known as reducibility over Q.> For an example, consider P(x)= x^2 + 2x + 1 = (x+1)(x+1), as a> polynomial reducible over Q, whereas P(x) = x^2 + 5x + 2, is an> example of a polynomial irreducible over Q.> The position Nora Baron is fighting for, is the claim that depending> on whether or not you can reduce a polynomial over rationals, it will> factor in certain ways, to where if it is irreducible, ALL of its> roots MUST not be coprime to any prime INTEGER factor of its constant> term.> Yes. You have stated that correctly.> So by the poster's beliefs now because x^2 + 5x + 2 is irreducible> over rationals, both its roots must have some non unit factor in> common with 2 based on that irreducibility alone.> Definitely true. Don't you agree? After all, each of theroots themselves is an algebraic integer, and the product of the rootsis 2. AND neither of the roots is a unit. It's pretty obvious, isn't it ???> but that's not a lot different from what was there before> when the factor was f^2.> When f is prime > 3, it is a LOT different.> But here you try to dismiss one constant factor--3--as a unimportant,> but try to hang on to f^2 which is also a constant factor with respect> to m. It's not that it is unimportant (though in fact it is - the case f = 3> is of no interest to you in your arguments either). It is that I don't> make any claims about what happens when f = 3. The > theorem that I use in that case does not apply anyway.> Hmmm...if that's correct, then how would it apply to> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f)?> When f = 3, this polynomial is not primitive. When, forexample, f = 5, m = 1, and u = 1, the polynomial inside theparentheses is irreducible. Do you now really want to see the rest of the argument?If so, why have you ignored it previously? Why don't you golook at Challenge of the Century ?> On what basis have you been arguing then?ematical logic, you are squirming trying to find> some way to hold on to your pet beliefs, against the math.> The math is the only reason I have for my pet beliefs.> Doesn't that bother you just a little bit? Nope.> That is you feel confident you are right, despite logical> inconsistencies in your position?> Have you stopped beating your wife?> Does it seem rational to you? Yes. > What seems irrational to me is to claim that > when f = 3, w1*w2 = 3^{2/3}, when in fact w1 and> w2 are, as you yourself have noted above, indeterminate> when f = 3. The f = 3 case adds no information to your> knowledge of the relationship between m and w1 and w2.> You claimed that it confirmed that w1 and w2 were constant.> It did no such thing.> I made a mistake. It's that simple.> Yup, I was saying w_1 w_2 = 3^{2/3} and that was wrong, which is> something that can be worked out mathematically.> I'm glad you caught that mistake as I was posting it all over the> place!> No problem! Glad to oblige!> There is an answer, which is found by following the math.> I totally agree.>It makes sense that they are anyway, as f^2 isn't a function of > m, but>I've seen that for some people the idea can take hold after seeing m=0highlighted.>>But if the w's were functions of m, then w_1 w_2 would equal 1,>without regard to the value of f, but it does not.> w1 = w2 = 1 and w3 = 3 is just one of the infinite range of possibilities. It is Example 1 above.> Well then, what makes you think the w's are *functions* of m, so that> m=0 would be a special case?> Where's the mathematical logic in your thinking?> See above. Unlike you, I do not make claims about> the special case f = 3. I say that when f = prime > 3 and> m is coprime to f, the w's are dependent on m. Prove> me wrong in THAT case and I will start to take notice.> Ok, so now f=3 is a special case. Before it was m=0 as your special> case and now f=3 is one as well.> It looks to me that when the math shows your beliefs to be wrong, you> find a way to call it a special case!>Therefore, the factorization is> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f =>> (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>where you'll notice that the b's are algebraic integers with m=1,f=sqrt(2), but that's a special case as generally they are not, which>shows a problem with the ring of algebraic integers.>> In this special case, P(x) does not even have> rational coefficients. It too is of no interest> or value for your main argument.> Hmmm...that's a fascinating attempt at dodging the relevant mathematics.> This is 180 degrees wrong! The RELEVANT mathematics are> not when f = 3. The cases of interest to YOU are f = prime > 3,> m coprime to f. Doesn't it seem a little odd for you to spend all> this effort in a subset where your own proofs are not concerned?> I go where necessity and the mathematical logic lead.> The point of my question was, there is no necessity to gowhere you did, and it doesn't do you any good anyway. You want to come to certain conclusions when f = 5, 7, 11, 13,etc.. You cannot get there by restricting yourself only to f = 3. It is like trying to deduce what is inside theforest by nibbling on a little of the foliage out at theedge.> Here I'm working to refute your popular position that reducibility> over Q actually forces factors to move around in a factorization,> which depends on claims that require that f^2, constant with regard to> m, and a factor of P(m) divides off from P(m) as a variable dependent> on m.> Yes, I am aware of what you are TRYING to do.> I've determined that I can destroy your case using f=3, which is what> I'm doing.> No. You have determined no such thing. Your argument here assumes exactly what you want to prove, that you can generalize from m = 0 to m <> 0. > As I pointed out in another thread, with m=1, f=sqrt(2), y=uf, you get> 2x^3 - 3xy^2 + y^3> which is reducible as it factors as> 2x^2 - 3xy^2 + y^3 = (x-y)(2x^2 + 2xy - y^2) and yes it is true that since y=uf, where f=sqrt(2), the y's are> irrational, but it doesn't change the fact that the polynomial is> reducible.> There are two things going on here. When you write> 2*x^3 - 3*x*y^2 + y^3> you are considering a polynomial in two variables. Indeed> that does factor in the obvious way. But when you subsitute y = sqrt(2), you are now > considering a polynomial in ONE variable (x). You are> back to the case in which you are interested. But this> polynomial in ONE variable has a constant term which> is irrational. You know perfectly well that it does not> factor with rational coefficients. > In your factorizations, you are invariably factoring a> polynomial in one indeterminate, x. That is why you > consider linear factors of the form (b1*x + u*f), etc.. > It is from that point of view that you should be considering> your polynomial, not as a polynomial in two variables.> What you said is not true. In fact, the factorizations I show are> those like> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = > (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)> which is in more than one variable.> You are considering only factorizations with respectto the polynomial indeterminate x. The other variables are not like the y in the bivariate polynomial above. In general you think of them asfixed constants. Unlike y, they do not appear explicitly inthe final factorization, i.e., in the linearterms of the general form (ai*x + ci).> I can *relate* such factorizations to simpler polynomials, where you> and others have argued.> ???> I find it interesting that you continue to defend your claims about> 2x^2 - 3xy^2 + y^3 = (x-y)(2x^2 + 2xy - y^2)> as you demonstrate a troubling inflexibility.> You applied this when y = sqrt(2). You wanted tohave it both ways: on the one hand, you wanted to saythat as a polynomial in TWO variables, it factored over the rationals. Then you wanted to let y = sqrt(2)and consider it as a polynomial in ONE variable, andmake the same claim. IT SIMPLY DOESN'T WORK. Apolynomial with irrational coefficients cannot possiblybe considered reducible over the rationals. It makesno sense to even consider it. It's not a matter offlexibility. > Well possibly it's because you realize that then I can use m=1(mod> sqrt(2)) to destroy your claims.> Nope. See above. You cannot have it both ways.> Now that makes the *second* time I've pointed that out to you.> Right, thanks. But sqrt(2) is still irrational, eh? Or did > that change recently in Georgia?> That's what's grand about mathematics, it's not particular to any> place or time.> Agreed. But answer the question about Georgia.> It seems to me that you demonstrate belief in something other than> mathematics.> The old mind-reader at work again.> Possibly you try to dismiss it because now using m=1(mod sqrt(2))> destroys your claim that reducibility matters, as for instance,> m=3=1(mod sqrt(2)) but now the resulting polynomial is *irreducible*> and your claims, where you believe the w's are functions of m, would> force factors of f to shift. You have lost me here. Are you saying that two values of m> that agree mod sqrt(2) are necessarily actually the same?> Your claim is to how factors in common with f will distribute within> the factorization where you have called m=0 a special case.> But with f=sqrt(2), m=1, I can demonstrate another case.> You've tried to challenge that because f=sqrt(2), and others might> claim that maybe m=1 is a special case, so I've pointed out that using> m=1(mod sqrt(2)) destroys your claims as then factors of f are fixed.> Think about it like this, if f=sqrt(2), then I can take the m=1 case,> and use m=1(mod sqrt(2)) to make factors of 2 stay in their place.> Do you understand?> You know, I just don't care about this example. It is notrelevant no matter how you cut it.>And here I've packed in a lot of information as well.>> Not enough, clearly.> Not if you refuse to follow mathematical logic.> I think you've shown through your posting behavior that you are EXTREMELY dedicated to the notion that I'm wrong, but the problem is> that the mathematical logic is against you.> You are correct that I think you are wrong. Saying I am > dedicated to that notion is not different from saying I am dedicated> to defending what I believe to be true. Is that a character flaw in> your eyes? Should I not do that? You can believe any number of things, even when they're false.> But in mathematics, you are supposed to adjust your beliefs if> necessary to the math.> Your beliefs are NOT more important than mathematical truth.> Can you understand?> Here again you are saying: I am infallible. I am uniquelyin possession of mathematical truth. If you disagree with me you are automatically wrong. Right? You are already back to saying you never make mistakes, right? Why in the HELL do you make that assumption? Given your history, the opposite assumption (that you areinvariably wrong) would be more justified. Have youbeen hearing voices from God telling you you are The One,or something? Have a little humility, man! So far, you've decided to go with your beliefs against the math.> My beliefs are based entirely on the math and nothing else> in this discussion.> I've proven that statement false.> Nosirree bob. You have assumed what you wanted to prove.In math, that's a no-no. Try to avoid it.First, with f coprime to 3, I now know that the factorization is>> P(m)/f^2 = (b_1 x + u)(b_2 x + u)(b_3 x + uf)>>as the w's are constant with respect to m, so I can just check at m=0,>which revealed that w_1 w_2 = 1. Now that doesn't necessarily force>w_1 and w_2 to each equal 1, but even if they were factors of 1, i.e.>unit factors, that would only change b_1 and b_2.>>So I have my factorization without regard to m in terms of where the f>goes, and then I point out that you can actually check my work usingm=1, f=sqrt(2), as then you get a polynomial which you can factor>rather simply. So you can actually get the values for the b's and>check them, and see that they are all algebraic integers, and all are>coprime to 2.>>However, usually, for f values that are coprime to 3, you don't get>b's that are algebraic integers, which shows a problem with the ring>of algebraic integers.>> Wrong! You *can* get algebraic integers, but *** not with> the properties you want ***, and there is no problem with> the ring of algebraic integers. Here is how things work when> f = 5, m = 1, u = 1, v = -1 + m*f^2, and> P(x) = (v^3 + 1)*x^3 - 3*v*x*(u*f)^2 + (u*f)^3:> P(x)/f^2 = P(x)/25 = 553*x^3 - 72*x + 5.> By the Magidin-McKinnon theorem (essentially proved earlier by > someone else [P. M. Cohn?]), this can be factored in the form 553*x^3 - 72*x + 5 = (b1*x + w1)*(b2*x + w2)*(b3*x + w3),> where b1, b2, b3, and w1, w2, w3 are algebraic integers. > You can show using elementary Galois theory that EACH of> w1, w2, and w3 is not coprime to f = 5. > Thus: a factorization of the desired form DOES exist, but it> does NOT have one of the properties that you desperately want.> No problem with the ring of algebraic integers, and no valid> proof for you. You lose on two counts. Too bad!> And your *belief* depends on the w's being functions of m, which is nonsensical, as follows from your own statements, like where you> noticed that with f=3, the w's are indeterminate, as 3 can divide off> an infinite number of ways.> It's amazing how you got this turned around. You claimed that the case f = 3 showed that the w's were constant. In fact in the> case f = 3, the w's are indeterminate. It clear from what you just> said that you actually understand this. The case f = 3 added > nothing to your knowledge of the behavior of the w's. Yet you > claim that *** I *** am being nonsensical !!! Incredible!> I was convinced by you that the w's are indeterminate, after I had the> wrong position that w_1 w_2 = 3^{2/3}, and later found out you were> wrong by checking the mathematical logic.> No. You just replaced one error with another. I must say, you are incredibly inventive and incrediblystubborn. You keep getting shot down, like Yul Brynner inthe old movie Westworld, and you just keep coming back with yet another bogus argument.> In your world, do people never change their minds?> Yes. I mean, Yup.> If you are someone who refuses to change their minds then that might> explain things.> I change my mind several times a day, just like myunderwear.> Yet now here you are claiming that the w's are functions of m.> I claim that the w's are dependent on m under the conditions> that f = prime > 3, and m coprime to f. What you have done> not only does not support your own conclusions in the special> no-interest case where f = 3, it doesn't even touch the cases> which are of genuine interest to both of us.> Here you've declared that f=3 is a special no-interest case which> goes against the math. That is NOT following the math.> Exactly the opposite is true.> Then prove it, mathematically.> Did. Previous post.> Don't *claim* one thing and do another.> Did. My conscience is clear on that one.> Prove your claims.> Wasn't once enough?>Now the nice thing about a mathematical proof is that if someone>disagrees they have to find some misstep.>> See above at #### ! The misstep in the current argument has been found.> No, but you have shown your own bias and refusal to follow> mathematical logic.> Really, there was nothing in my post but mathematical logic. Sorry it didn't support your beliefs.> Then discussions should be quick.> I wish they were quicker than this one!> You show the logical chain in your reasoning and that will be it.> Right. See all of above. Or go have a look at Challenge of theCentury.> Show the mathematical logic that you believe supports your position,> if you can.> Done. See all of above, plus previous post, plus several dozenothers.Unfortunately, people can *say* that proof is not a proof, even when>it is, just like if you tried to say you were human, and not a dog,>someone might dispute any proof you might give, claiming it false.> In this case, you have tried to use an irrelevant > red-herring argument to show what you want. Unfortunately, in the special case you selected, the number f (= 3) does factors *** non-uniquely *** through the linear terms of your> polynomial factorization, and you end up being able to> conclude:> *** N O T H I N G *** about the cases in which you are interested. But you have made progress. Do you realize how long it> took us to get through to you that there is actually a> nontrivial problem with generalizing from m = 0 to> m <> 0 ? Do you realize how many incorrect arguments> you have already burned through (including the present> one) in trying to handle that problem? Do you realize> that all of this is a waste of time, because your > main claims have already been shown to be false and> cannot be fixed by twiddling with the details?> Nora B.> And readers should note that Nora Baron here arrogant and presumably confident, is still fighting to claim that f^2 divides off of a> polynomial as a function of m, though it is itself constant with> regard to m, when the poster has spent a lot of effort trying to claim> that 3 divides off in an inconsequential way, when f=3.>> Well, duh. Yes, that is what I was saying. I agree that I spent a> lot of time on an inconsequential case. I was simply trying to show that your conclusions *even in that case* were not justified. At least> you got the point this time, so I don't think it was a complete waste.> However, the arguments you used would destroy your own claims about> f^2 dividing off from P(m) in some particular way.> No, I am not going to give an inch on that. See above.> So you're trapped both by what you said, and by the mathematical> logic.> Oddly, I don't feel trapped at all.> You can, of course, restate your position, if you wish.> I don't wish.> The point is that the poster Nora Baron is not making sense.>> It's clear from what you have said here that you understood what I was> saying, and even, I daresay, that you were surprised by it. So clearly, > it is not that what I said did not make sense. It is that you did not > like the conclusion.> Nora B. > That is not correct. I *accepted* your conclusion and then found out> that it was false, when I checked the math.> No - you were right when you accepted it. Then yourelapsed.> Now you have the option to follow the math, or stick with false> beliefs.> I invariably go with the former. Nora B.> James Harris === > In which case, I am VERY ANNOYED that you continue to act> as if you are infallible, and frequently accuse the rest of > us of lying. Nora Baron, you have relinquished any right to be very annoyed atthe behaviour of James Harris. Nora Baron, you have made *HUNDREDS*of replies to his posts, going back over two and a half years now.There is no *possible* way it took until now for the clue train tosmack you broadside. James Harris displays a sickness, and is clearly*NOT* amenable to change. The role he has settled into on Usenet, isthe one he is comfortable with, and one he will likely keep until theday he dies.You, and some other posters, have displayed signs of codependancy. Asif James' sickness draws you to him, like flies on .James will *NOT* change. Whether you change is up to you. Arguingwith him is like arguing with a rock, or your bathroom wall. If youcontinue to define your online life by replying to his trolling, youare most certainly a diseased person also.This is my last post to you on this subject, Nora Baron, because asfor myself I *refuse* to be drawn into James' sickness for years andyears on end. Nora B.> James HarrisFlatrings === [snip]> You, and some other posters, have displayed signs of codependancy. As> if James' sickness draws you to him, like flies on .Say, aren't you the same guy who posts all the James Harris parodies? (Talk about codependancy!)--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 === > What I've noticed is that Arturo Magidin works VERY hard to be> believed.He doesn't have to work hard to be believed. The things he says areeasily believable and are backed up with solid math.> authoritative or looks mathematical, but he rarely actually proves> anything relevant to his central objections.Your failure to understand his arguments and their relevance doesn'tmake them irrelevant.-- 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 === > What I showed in my post is that w1*w2 can be ANY two algebraic integer> factors of f = 3. It is NOT necessarily the case that w1*w2 = 3^{2/3}> in that case. The case f = 3 does not give you any information about> the w's.> Well it turns out I was in error > ... not for the first time, or, I suspect, the last.Oh, so now you want to attack me for admitting a mistake.That tells a lot about you Nora Baron.Why don't you tell the newsgroups who you actually are and quit hidingbehind the pseudonym? > as the answer is given by considering> the factorization> P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)> as with f=3, it's clear that *each* > each what?Each of the a's has 3 as a factor when f=3, and that is without thedependency on m that you seem so dedicated on claiming exists when fis coprime to 3.> has 3 as a factor, which gives you> P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - > (-1+m 3^2 )x u^2 + u^3 = > (a_1/3 x + u)(a_2/3 x + u)(a_3/3 x + u).> What I showed in my previous post implies that if> a1, a2, and a3 are the negatives of the roots of > the polynomial > u^3 - 8*u^2 - 19,> then a perfectly legit factorization is:> [****] (a1*x + 1)*(a2*x + 1)*(27*a3*x + 27)> which happens to equal> 27*(a1*x + 1)*(a2*x + 1)*(a3*x + 1).> I think you can work out the reasoning> for yourself on that. If not, let me know.But Nora Baron the a's are NOT the negatives of the roots of u^3 - 8*u^2 - 19as in fact, P(m) = f^2((m^3 f^4 - 3m^2 f^2 + 3m) x^3 - 3(-1+mf^2 )x u^2 + u^3 f) = (a_1 x + uf)(a_2 x + uf)(a_3 x + uf)so the a's are the roots of a^3 + 3(-1+9m)a^2 - ((-1+9m)^3+1).> Now using the b's and w's gives> P(m)/3^2 = 3((m^3 3^3 - 3^2 m^2 + m) x^3 - (-1+m 3^2 )x u^2 + u^3) = > (b_1 x + u w_1)(b_2 x + u w_2)(b_3 x + u w_3)> but at m=0, I have> P(0)/3^2 = u^2(3x - 3u) = u^2(b_3 w_1 w_2 - 3u), so> and dividing off the last 3 gives> P(m)/3^3 = (m^3 3^3 - 3^2 m^2 + m) x^3 - > (-1+m 3^2 )x u^2 + u^3 = > (b_1 x + u)(b_2 x + u)(b_3/3 x + u)> Nope, this is NOT OK. Why? Because you are assuming > what you want to prove. You want to show that the> factorization when m <> 0 is similar to that when m = 0.> Here m = 3. In case you have not noticed, 3 is not equal> to 0.But m does not equal 3, as readers can verify by looking above at theexpressions where they see m all over the place, as well as 3, andthere is no claim that m=3. > Plus, if you look at what I said above at [****}, you > will see a counterexample.I'm curious about how you'd like you to explain the weird statementsyou've already made, and I'll finish out by focusing on the last oneI've included.Here's what you had above:> What I showed in my previous post implies that if> a1, a2, and a3 are the negatives of the roots of > the polynomial > u^3 - 8*u^2 - 19,> then a perfectly legit factorization is:> [****] (a1*x + 1)*(a2*x + 1)*(27*a3*x + 27)But in fact, the a's are the roots of a^3 + 3(-1+9m)a^2 - ((-1+9m)^3+1).Yet after you said if in one place, further down in your post yousaid:> Plus, if you look at what I said above at [****}, you > will see a counterexample.Why don't you try and explain yourself to the newsgroups?James Harris === [snip]> Why don't you tell the newsgroups who you actually are and quit hiding> behind the pseudonym?That's not a math issue. Perhaps James Harris is an acronym for Mr. J. Harie Ass. So what? Argumentum ad hominemis a fallacy.A better question is: Why don't you post one of the numbers you claim to have discovered which *should be* analgebraic integer, but which is *left out* of the ring of algebraic integers? Those numbers are the basis for yourrepeated accusations that math professors are teaching lies to students and form the basis of your threats to sue theuniversities. Here's a great opportunity to post *one* such number for the enlightenment of students andmathematicians alike.I'll make it easy for you.I, James Harris, have found the following number (numeric quantity) which should be an algebraic integer (because itis the root of a monic polynomial with integer coefficients), but which is not:____________This is a much simpler challenge than the only posed by Nora Baron, because her challenge requires you to think andunderstand. Mine only requires that you post a number you claim to have already found.--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 === http://www.geocities.com/ dharwadker/Has this proof been peer reviewed? Is it correct or is it just garbage?Charles === > http://www.geocities.com/dharwadker/> Has this proof been peer reviewed? Is it correct or is it just garbage?I found it impossible to read on my browser (Mozilla).The text was fine; but the equations appeared to be in some strange format.Could anyone decipher it?-- Timothy Murphy tel: +353-86-233 6090 === Is (sqrt(sqrt(5)+3/2)-cubrt(sqrt(14/22)-9))^2/5 an 'algebreic' number?It's composed completely of a combination of rational numbers raisedto rational exponents, so shouldn't it be algebreic? As in,nontranscendental?(...Starblade Riven Darksquall...) === > Is (sqrt(sqrt(5)+3/2)-cubrt(sqrt(14/22)-9))^2/5 an 'algebreic' number?> It's composed completely of a combination of rational numbers raised> to rational exponents, so shouldn't it be algebreic? As in,> nontranscendental?Yes, any such number is algebraic,and so -- by definition -- not transcendental.(However, the converse is not true;not every algebraic number can be expressed in such a form.)-- Timothy Murphy tel: +353-86-233 6090 === >Is (sqrt(sqrt(5)+3/2)-cubrt(sqrt(14/22)-9))^2/5 an 'algebreic' number?Yes.>It's composed completely of a combination of rational numbers raised>to rational exponents, so shouldn't it be algebreic? Well, there's a little more to the proof than that. But in factthe algebraic numbers form an algebraically closed field,from which it follows that the number above is algebraic.>As in,>nontranscendental?>>(...Starblade Riven Darksquall...)************************David C. Ullrich === Is (sqrt(sqrt(5)+3/2)-cubrt(sqrt(14/22)-9))^2/5 an 'algebreic' number?> Yes.>It's composed completely of a combination of rational numbers raised>to rational exponents, so shouldn't it be algebreic? > Well, there's a little more to the proof than that. But in fact> the algebraic numbers form an algebraically closed field,> from which it follows that the number above is algebraic.>As in,nontranscendental?>>(...Starblade Riven Darksquall...)> ************************> David C. UllrichOkay, I understand. But is the number of such algebreic numberscountably infinite or uncountably infinite?(...Starblade Riven Darksquall...) === Is (sqrt(sqrt(5)+3/2)-cubrt(sqrt(14/22)-9))^2/5 an 'algebreic' number? Yes.It's composed completely of a combination of rational numbers raised>>to rational exponents, so shouldn't it be algebreic? Well, there's a little more to the proof than that. But in fact>> the algebraic numbers form an algebraically closed field,>> from which it follows that the number above is algebraic.As in,>nontranscendental?>>(...Starblade Riven Darksquall...) ************************ David C. Ullrich>>Okay, I understand. But is the number of such algebreic numbers>countably infinite or uncountably infinite?The algebr_a_ic numbers are countable.>(...Starblade Riven Darksquall...)************************David C. Ullrich === >Is (sqrt(sqrt(5)+3/2)-cubrt(sqrt(14/22)-9))^2/5 an 'algebreic' number?> Yes.>It's composed completely of a combination of rational numbers raised>to rational exponents, so shouldn't it be algebreic? > Well, there's a little more to the proof than that. But in fact> the algebraic numbers form an algebraically closed field,> from which it follows that the number above is algebraic.As in,>nontranscendental?>>(...Starblade Riven Darksquall...)> ************************> David C. Ullrich> Okay, I understand. But is the number of such algebreic numbers> countably infinite or uncountably infinite?Countably. That follows from noting that there are countablymany polynomials with integer coefficients. - Randy Suppose p,q, and r are any three consecutive primes. Is there a constant Ksuch that there always exist nonzero a,b,c with a*p+b*q+c*r=0 and 0<=a+b+c Suppose p,q, and r are any three consecutive primes. Is there a constant K> such that there always exist nonzero a,b,c with a*p+b*q+c*r=0 and 0<=a+b+cLet the three consecutive primes be p, p + s, p + t, s < t. >Let a = -t + s, b = t, c = -s. >Then ap + bq + cr = (-t + s)p + t(p + s) + -s(p + t) = 0 >and a + b + c = 0.>Yes. Clearly I should have thought about this a little more.Rich === Maybe more interesting to use the magnitudes of a,b,c. Thus:Question: Does there exist a constant K so that for any threeconsecutive primes p,q,r there exist integers a,b,c with the propertythat ap+bq+cr=0 and |a|+|b|+|c| < K?The solution to your original question obviously won't work, sinceusing r3769's notation, either s or t can become arbitrarily large.(There are arbitrarily long stretches of composite numbers.)So a related question (possibly easy?) is the following:Question: Given a positive integer K, is it always possible to findthree consecutive primes p,q,r so that q > p+K and r > q+K? (If so,there's an obvious generalization to more than three consecutiveprimes.)>Let the three consecutive primes be p, p + s, p + t, s < t. >Let a = -t + s, b = t, c = -s. >Then ap + bq + cr = (-t + s)p + t(p + s) + -s(p + t) = 0 >and a + b + c = 0.>> Yes. Clearly I should have thought about this a little more.> Rich === suppose that you have 2 different sets, S1 and S2. there are many,many sample points in each one. S1 has a mean of x1 and a standarddeviation, sd, of sd1. moreover, S2 has a mean and sd of x2 and sd2. moreover, S1 and S2 are slightly correllated with each other with R =-0.4.suppose that i created a new set called S* with 45% of its samplepoints from S1 and 55% from S2, what would the new standard deviationand mean be? is there an algorithm/calculation for this?finally, suppose that you have 3 different sets, S1, S2, and S3. there are many, many sample points in each one. S1 has a mean of x1and a standard deviation, sd, of sd1. moreover, S2 has a mean and sdof x2 and sd2, and s3 has a mean of x3 and sd of sd3. S1, S2, and S3are all correllated with each other like this: S1 S2 S3S1 1.00 -0.55 0.22S2 -0.55 1.00 0.02S3 0.22 0.02 1.00and suppose that i create a new set with a mixture of k1% of S1, k2%of S2, and k3% of S3 (k1 + k2 + k3 = 1.00). what would be the newmean and sd of this? does a math exist for these kinds of problems? finally, what measurement of correllation do i use: R^2, or R? === > rational number + rational number = rational number> and> rational number + irrational = irrational> This is what I have:> 1) since all rational numbers can be expressed as a ratio of two integers, n=p/q> then p1/q1 + p2/q2 = (p1q2+p2q1)/q1q2 which is still a ratio of integers> i.e. 1*4+2*3/4*3=10/12 2) using the above, with irrationals, there is no ratio such that n=p/q>> Suppose that rational + irrational = rational, > then rational - rational = irrational> which contracdicts what you proved in (1), so it must be the case that> rational + irrational = irrational.>> i.e n=sqrt(x)> so that p/q + sqrt(x) ...> that is where I begin to get really informal. > anyone wanna let me know how I could improve on this?> would induction or an indirect proof be of any use? > joshrational - rational' Now I get it.So many wonderful ways of putting it. I am beginning to see how thisall works.Josh === > what would be the best way to prove>> rational number + rational number = rational number> and> rational number + irrational = irrational>> This is what I have:>> 1)> since all rational numbers can be expressed as a ratio of two integers,n=p/q> then p1/q1 + p2/q2 = (p1q2+p2q1)/q1q2 which is still a ratio of integers>> i.e. 1*4+2*3/4*3=10/12>> 2) using the above, with irrationals, there is no ratio such that n=p/q> i.e n=sqrt(x)> so that p/q + sqrt(x) ...> that is where I begin to get really informal.>Its just a redo of (1)Let n be irrationalAssume p/q + n = r/sn = r/s - p/qNow finish up the right hand side and look for a contradiction-Tralfaz === > what would be the best way to prove>> rational number + rational number = rational number> and> rational number + irrational = irrational>> This is what I have:>> 1)> since all rational numbers can be expressed as a ratio of two integers,n=p/q> then p1/q1 + p2/q2 = (p1q2+p2q1)/q1q2 which is still a ratio of integers>> i.e. 1*4+2*3/4*3=10/12>> 2) using the above, with irrationals, there is no ratio such that n=p/q> i.e n=sqrt(x)> so that p/q + sqrt(x) ...> that is where I begin to get really informal.>Its just a redo of (1)Let n be irrationalAssume p/q + n = r/sn = r/s - p/qNow finish up the right hand side and look for a contradiction-Tralfaz === > what would be the best way to prove> rational number + rational number = rational number> and> rational number + irrational = irrational> This is what I have:> 1)> since all rational numbers can be expressed as a ratio of two integers, n=p/q> then p1/q1 + p2/q2 = (p1q2+p2q1)/q1q2 which is still a ratio of integers> i.e. 1*4+2*3/4*3=10/12> 2) using the above, with irrationals, there is no ratio such that n=p/q> i.e n=sqrt(x)> so that p/q + sqrt(x) ...> that is where I begin to get really informal. > anyone wanna let me know how I could improve on this?> would induction or an indirect proof be of any use? > joshAssume that x + y = z, x rational, y irrational, z rational. Then y = z - x. But rational - rational is rational, so the assumption is wrong. === 1)a= sqrt(3+b) , where b = sqrt(17)c= sqrt(5+3*b)d =sqrt(2)Sum = (-d*a) - (2*b) + (b*d*a) - (2*c*d) + 2*c*a = 142)The sum of two irrational: The most common example to remember: sin^2(A)+cos^2(A)=1,where for some A both sin^(A) and cos^2(B) are two irrationals.Tapiowould be the best way to prove>> rational number + rational number = rational number> and> rational number + irrational = irrational>> This is what I have:>> 1)> since all rational numbers can be expressed as a ratio of twointegers, n=p/q> then p1/q1 + p2/q2 = (p1q2+p2q1)/q1q2 which is still a ratio ofintegers>> i.e. 1*4+2*3/4*3=10/12>> 2) using the above, with irrationals, there is no ratio such thatn=p/q Suppose that rational + irrational = rational,> then rational - rational = irrational>> which contracdicts what you proved in (1), so it must be the casethat>> rational + irrational = irrational.> i.e n=sqrt(x)> so that p/q + sqrt(x) ...> that is where I begin to get really informal.>> anyone wanna let me know how I could improve on this?> would induction or an indirect proof be of any use?> josh>> rational - rational' Now I get it.> So many wonderful ways of putting it. I am beginning to see how this> all works.> Josh === I am anxious to university registration fee for a term at your nation.in my case(korea)if national university, usually 850~1300 dollarif private university, 2000~2500 dollaryour nation ?? USA, Britain, Switzerland, Germany....etc...please, tell me what price~ === >>Is this homework? <>am trying to figure out if 'A' and 'w' are enough info to enable one to find'b' and 'c'.>>Ok.>>A = pi(c^2-b^2)>w = c-b [not b-a as you give above]>>So,>So, since it's a programming project and not homework, do you get a share of the sales?As a rough estimate, the flat rate is .1 hr * $60/hr. = $6. Close? (Depends on what your professional hourly rate is, and I don't know your profession.)Jon Miller === >>Is this homework? <<>>I kinda wish it was, but I've been out of school for many more yearsthan I>>care to admit and my algebra/trig/geometry is quite rusty.>>I>am trying to figure out if 'A' and 'w' are enough info to enable one tofind>>'b' and 'c'.>Ok.>>A = pi(c^2-b^2)>w = c-b [not b-a as you give above]>>So,>> So, since it's a programming project and not homework, do you get a> share of the sales?Sadly, I forgot to negotiate a contract before blurting out the answer.Darn.> As a rough estimate, the flat rate is .1 hr * $60/hr. = $6. Close?> (Depends on what your professional hourly rate is, and I don't know> your profession.)-- Clive Toothhttp://www.clivetooth.dk === > so evidently something's going on here. you sure about that 87382,> though? the encyclopedia predicts 2^18.Now I've implemented a symbolic Xor (see below) and the sequence isproved until length 62: 1, 3, 7, 7, 31, 63, 15, 15, 511, 63, 2047, 1023, 511, 16383, 31, 31,4095, 87381, 4095, 1023, 127, 4095, 8388607, 2097151, 255, 67108863,1048575, 511, 536870911, 1073741823, 63 You can find it at OEIS:http://www.research.att.com/cgi-bin/access.cgi/as/njas/ sequences/eisA.cgi?Anum=A086839 (I've send a comment to add the new elements).The program with symbolic Xor calculating:public class Rule90 { public static void main(String args[]) { long mul2[] = new long[64]; long start = 1; for (int i = 0; i < 64; i++, start *= 2) mul2[i] = start; long pattern[] = new long[64]; long next[] = new long[64]; long reverse[] = new long[64]; for (int len = 2; len < 64; len += 2) { /* init pattern and reverse check */ for (int i = 0; i < len; i++) { pattern[i] = mul2[i]; reverse[i] = mul2[len - i - 1]; } /* calculate steps needed for reversing */ long steps = 0; while (true) { /* calculate next step */ next[0] = pattern[1]; for (int i = 1; i < len - 1; i++) { next[i] = pattern[i - 1] ^ pattern[i + 1]; } next[len - 1] = pattern[len - 2]; /* check for reverse */ boolean found = true; for (int i = 0; i < len; i++) { if (pattern[i] != reverse[i]) { found = false; break; } } if (found) break; /* swap pattern and next */ long tmp[] = next; next = pattern; pattern = tmp; /* increment step count */ steps++; } /* print number of steps */ System.out.println(steps + , ); } }}-- Frank Bu, fb@frank-buss.dehttp://www.frank-buss.de, http://www.it4-systems.de === Let A be a relational system and let L be a f.o.language for predicatecalculus. How we prove that the formula((Vx)f(x)) -> f(y)is satisfable in A for every A (s.t. L is appropriate for A) we consider???For brief info seehttp://mathworld.wolfram.com/Satisfaction.html . === >Let A be a relational system and let L be a f.o.language for predicate>calculus. How we prove that the formula>>((Vx)f(x)) -> f(y)>>is satisfable in A for every A (s.t. L is appropriate for A) we consider???Let me change notation a bit (A becomes M, f(x) becomes P(x), /x becomesEx).Let M be any L-structure where L contains a 1-place predicate P. Let P^M bethe extension of P in M. You want to show that There is an assignment v such that (M,v) |= ExP(x) -> P(y).(v is an assignment of values to variables. I.e., v : var(L) -> dom(M). Thenotation (M, v) |= phi means that the formula phi is true when interpretedby the structure M, relative to assignment v.)Case 1. Suppose P^M is empty. Then, ExP(x) is false in M. Hence, M |=~ExP(x). Recall that (by truth tables), if ~A is true, then the materialconditional A->B is true, for any formula B. So, for any assignment v, (A,v)|= ExP(x) -> P(y).Case 2. Suppose P^M has an element, say a. Then M |= ExP(x). Define anassignment v by letting v(y) = a (i.e.,. v assigns the object a to thevariable y). Then, (M, v) |= P(y). So, by the truth table for ->, (A, v) |=ExP(x) -> P(y).--- Jeff === >>Let A be a relational system and let L be a f.o.language for predicate>>calculus. How we prove that the formula>>((Vx)f(x)) -> f(y)>>is satisfable in A for every A (s.t. L is appropriate for A) weconsider???>>Let me change notation a bit (A becomes M, f(x) becomes P(x), /x becomes>Ex).>>Let M be any L-structure where L contains a 1-place predicate P. Let P^M be>the extension of P in M. You want to show that>> There is an assignment v such that (M,v) |= ExP(x) -> P(y).>>(v is an assignment of values to variables. I.e., v : var(L) -> dom(M). The>notation (M, v) |= phi means that the formula phi is true wheninterpreted>by the structure M, relative to assignment v.)>>Case 1. Suppose P^M is empty. Then, ExP(x) is false in M. Hence, M |=>~ExP(x). Recall that (by truth tables), if ~A is true, then the material>conditional A->B is true, for any formula B. So, for any assignment v,(A,v)>|= ExP(x) -> P(y).Whoops. Last bit should read: (M, v) |= ExP(x) -> P(y).>Case 2. Suppose P^M has an element, say a. Then M |= ExP(x). Define an>assignment v by letting v(y) = a (i.e.,. v assigns the object a to the>variable y). Then, (M, v) |= P(y). So, by the truth table for ->, (A, v) |=>ExP(x) -> P(y).Again, should read: (M, v) |= ExP(x) -> P(y).--- Jeff === > I'm searching for a list of tautology formula of symbolic logic.> If anybody knows,please let me know where on the net!!!It's fairly trivial to write a program to list them. For example:Generate all wffs (formulas - up to a certain size) and evaluate eachfor all values of the variables. If all such evaluations produce TRUEthen output it. To generate all wffs, one simple way is to use thefact that P, Q, R, . . . are wffs, and if X and Y are wffs, so are ~Xand X^Y and XvY etc, (for whatever logical connectives you choose touse). I have had to throw together a subroutine to do this a numberof times in my research.If there is interest, I will post the first few hundred tautologies. Which connectives (^, v, ~, =>, <=>, etc.) and variables (p, Q, R,etc.) shall I use?Charlie VolkstorfCambridge, MA === Dear NG,Heres a quickie.. Given epsilon (small real number). What is the smallest integer N, such that sum_(k=N to infinity) 1/k^2 <= epsilon.Sincerely,Jose Capco === > Dear NG,> Heres a quickie.. > Given epsilon (small real number). What is the smallest integer N, such that > sum_(k=N to infinity) 1/k^2 <= epsilon.> Sincerely,> Jose Capco> Probably solving for that N is not possible in elementary form.But the sum is close to the integral x=N to infinity of 1/x^2 whichcan be determined in closed form. Then try a few nearby integers toget your answer. === >> Given epsilon (small real number). What is the smallest integer N, such that >> sum_(k=N to infinity) 1/k^2 <= epsilon. >Probably solving for that N is not possible in elementary form.>But the sum is close to the integral x=N to infinity of 1/x^2 which>can be determined in closed form. Then try a few nearby integers to>get your answer.Well, there are just two possibilities: if f(N) is your sum,1/N < f(N) < 1/(N-1) so if 1/M <= epsilon < 1/(M-1), you want either N = M or N = M+1. More precise estimates are available,e.g. 1/(N-1/2) < f(N) < 1/(N-1/2 + 1/(12 N) + 1/(24 N^2))where the difference between the left and right sides is O(1/N^3),so for most values of epsilon it will be possible to tell whetherit should be M or M+1 without having to evaluate f(N).Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === >> Dear NG,>> Heres a quickie.. >> Given epsilon (small real number). What is the smallest integer N, such that >> sum_(k=N to infinity) 1/k^2 <= epsilon.>> Sincerely,>> Jose Capco>Probably solving for that N is not possible in elementary form.>But the sum is close to the integral x=N to infinity of 1/x^2 which>can be determined in closed form. Then try a few nearby integers to>get your answer.It can be reduced even further; the sum is between 1/N and 1/(N-.5),with 1/(N-.5) being closer, and relatively accurate for large N.-- This address is for information only. I do not claim that these viewsare those of the Statistics Department or of Purdue University.Herman Rubin, Department of Statistics, Purdue University === on a rock and hollered:>or would you just as soon I shut-up whether I'm right or not>because you're just sick of me,Bingo.(followups set: sci.skeptic)-- No collection of individuals is less vindictive than an audience at amateur theatricals. - P. G. Wodehouse, _The Intrusion of Jimmy_ === Can't touch this, it's HAMMER TIME === Can't touch this, it's HAMMER TIME === Can't touch this, it's HAMMER TIME === Can't touch this, it's HAMMER TIME === Please help me figure out how to solve this problem. This is with relationto ratio and root tests.If {a_k} is any sequence of positive numbers, thenlim inf _{k->infty} a_{k+1}/a_k leq lim inf _{k -> infty} a_k^{1/k}leqlim sup _{k->infty} a_k^{1/k} leq lim sup _{k->infty} a_{k+1}/a_k === >Please help me figure out how to solve this problem. This is with relation>to ratio and root tests.>>If {a_k} is any sequence of positive numbers, then>>lim inf _{k->infty} a_{k+1}/a_k leq lim inf _{k -> infty} a_k^{1/k}Then there exists N so that a_{k+1}/a_k > L' for all k >= N.Think about this - it follows that a_k > ________ for all k > N,and then that implies that lim inf _{k -> infty} a_k^{1/k} > L'.Since that holds for all L' < L, in fact lim inf _{k -> infty} a_k^{1/k} >= L.>leq>>lim sup _{k->infty} a_k^{1/k} leq lim sup _{k->infty} a_{k+1}/a_k>>************************David C. Ullrich === > Please help me figure out how to solve this problem. This is with relation> to ratio and root tests.> If {a_k} is any sequence of positive numbers, then> lim inf _{k->infty} a_{k+1}/a_k leq lim inf _{k -> infty} a_k^{1/k}> leq> lim sup _{k->infty} a_k^{1/k} leq lim sup _{k->infty} a_{k+1}/a_kSuppose liminf a_{k+1}/a_k = L, and suppose M < L.Then a_{k+1}/a_k > M for all k >= n.Hence a_k > a_N M^{k-n} for k > n.Thus a_k > C M^k for some constant C and all k > n.So a_k^{1/k} > C^{1/k} M for all k > n.Since C^{1/k} -> 1 as k -> infty, ...-- Timothy Murphy tel: +353-86-233 6090 === > Given a square matrix G, how do I solve the equation> X = I + G + X*X> ? Any references to the literature? Can computer algebra systems do that?> (I know the solution of X = I + G + G*X, it's X=(I-G)^(-1), but blissfully> unaware of the method;-)Some Maple code for matrix G ...with(linalg):G:=matrix(6,6,[[0,0,0,0,0,0],[1,0,0,0,0,0],[ 1,0,0,0,0,0],[1,0,0,0,0,0],[0,0,1,1,0,0],[0,1,0,0,1,0]]); ifiszero(evalm(G^4)) then print('G'^4=0,`so`,T=1+G+T*T,`hassolution`,T=collect(convert( series(RootOf(T=1+G+T*T,T),G,4),polynom),RootOf));T=collect( convert(series(RootOf(T=1+G+T*T,T),G,4),polynom),RootOf,evalm) ; fi;Chris === > I'm looking for an (possibly efficient) algorithm to solve systems of> quadratic equalities and inequalities where the number of quadratic> terms (i.e. x*y or x^y) is small.> Losely speaking, I have a lot of linear constraints, but sometimes> there could be some products.x^y is quadratic?--Ron Bruck === > Let z = sum ( i = 0,1,2,3,... ) 1/(2^(f(i)))>> where>> f(x) = x iff the Continuum Hypothesis is true> f(x) = x+1 iff the Continuum Hypothesis is false>> Is z well defined? Is z a number? Is z some sort of weird> Shroedinger's Cat (sp.)? Is z complete gibberish?Well, clearly z is either sum 1/2^i or sum 1/2^(i+1) depending on whetheryou believe the continuum hypothesis.You might as well propose belief in the lord our god.Roland--Roland and Lisa Paterson-JonesForest Lodge, Stirrup Lane, Hout Bayhttp://www.rolandpj.com/forest-lodgemobile: +27 72 386 8045 === > * Doug B.>> Let z = sum ( i = 0,1,2,3,... ) 1/(2^(f(i))) where f(x) = x iff the Continuum Hypothesis is true>> f(x) = x+1 iff the Continuum Hypothesis is false Is z well defined? Is z a number? Is z some sort of weird>> Shroedinger's Cat (sp.)? Is z complete gibberish?>> It depends on your mathematical philosophical position:>> An intuitionist will say it is not a number.> A platonist and a formalist think it is a number.Why would a formalist think that z is a number?How would a formalist interpret true here?(If you mean: a formalist would interpret true to mean provable,then certainly z is a number -- a known quantity in this case. If youmean something else, then please elaborate.)-- Jesse Hughes Depression hits more people than thought. --headline in Lexington, KY newspaper, as reported on NPR's Morning Edition === Bishop and Goldberg said that the standard topology on R^n is d_p(x,y) = [sum |u^i x|^p + |u^i y|^p]^(1/p)for p >= 1.I don't think they defined the u^i, are they just some operator thatpicks a component from a representation of a point?I don't think they explained why p>=1, although it may have been in aproblem that I solved incorrectly. Looks to me like they'd all bestrongly equivalent if p!=0, for instance. And what's wrong with p=1/2?What can we say about a type of Pythagorean theorem that looked like r = (sqrt|x2-x1| + sqrt|y2-y1| + sqrt|z2-z1|)^2They sure don't have a lot of pictures in their book.-- A good plan executed right now is far better than a perfect planexecuted next week. -Gen. George S. Patton === > Bishop and Goldberg said that the standard topology on R^n is> d_p(x,y) = [sum |u^i x|^p + |u^i y|^p]^(1/p)> for p >= 1.They don't.-- Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.html The League of Gentlemen === >>Bishop and Goldberg said that the standard topology on R^n is>> d_p(x,y) = [sum |u^i x|^p + |u^i y|^p]^(1/p)>>for p >= 1.That's nonsense - how does the formula actually read in the book?>I don't think they defined the u^i, are they just some operator that>picks a component from a representation of a point?Probably.>I don't think they explained why p>=1, although it may have been in a>problem that I solved incorrectly. Looks to me like they'd all be>strongly equivalent if p!=0, for instance. And what's wrong with p=1/2?If 0 < p < 1 then the correct version of the formula above does not define a metric. (The fact that d(x,y) <= d(x,z) + d(z,y) needs to be proved; for p < 1 it can't be proved because it's false.)>What can we say about a type of Pythagorean theorem that looked like>> r = (sqrt|x2-x1| + sqrt|y2-y1| + sqrt|z2-z1|)^2>>They sure don't have a lot of pictures in their book.************************David C. Ullrich === >>Bishop and Goldberg said that the standard topology on R^n is>> d_p(x,y) = [sum |u^i x|^p + |u^i y|^p]^(1/p)>>for p >= 1.> That's nonsense - how does the formula actually read in the book?It's a category mistake too. That's a metric not a topology.The book says something like[sum_i|u^i x - u^i y|^p]^(1/p),u^i having been previously defined as the i-th projection fromR^n to R (ugh!). >>They sure don't have a lot of pictures in their book.What is the use of a book without pictures or conversations? :-)-- Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.html The League of Gentlemen === In the excellent classic scifi novel The Demolished Man by AlfredBester there is the following song:Eight, sir; seven, sir;Six, sir; five, sir;Four, sir; three, sir;Two, sir; one!Tenser, said the Tensor.Tenser, said the Tensor.Tension, apprehension,And dissension have begun.I don't know much about what tensor analysis is all about or what atensor is, but I'm wonder if a simple layman's explaination of whatone is would help to better appreciate this song. Do tensors havesomething to do with tension? With reducing eight to one? Is tenseralso a pun on ten, sir!? (Except the countdown begins at eight andnot ten, but maybe the nature of tensor analysis has something to dowith that?)Well, thank you for any explainations! === |I don't know much about what tensor analysis is all about or what a|tensor is, but I'm wonder if a simple layman's explaination of what|one is would help to better appreciate this song.Tensors are geometric constructions generalizing vectors. For ainformal expository discussion you can look athttp://www.math.ucr.edu/home/baez/gr/gr.html.They are used in general relativity (hence the gr), which wasEinstein's theory of gravitation, still the best available theoryof gravitation.|Do tensors have something to do with tension?Yes.Stress (and tension) is described using the stress tensor. Perhapsit will give an idea of how they generalize vectors. Forces are givenby vectors. But stress isn't generally just a matter of forces beingapplied along a single axis. If we place an imaginary plane withina solid, the forces exerted by the solid on one side on the solid onthe other side (either tension or compression, possibly with shear)depend upon the orientation of the plane you are putting there. Butthis dependence is well-behaved, and can be determined from theforces exerted across just three planes, parallel to the xy, xz, andyz planes.So in order to describe stress we wind up using 9 components,rather than just 3 for an ordinary vector. If we rotate the coordinatesystem, the components transform in a certain way, so it's moreof a geometric type of thing than just 9 quantities lumped together,just like vectors are more geometric than just 3 quantities thatbelong together.Part of the magic of general relativity is that three space coordinatesplus time can be represented mathematically as a four-dimensionalcontinuum. In that context, instead of just 9 components for thestress, there's a similar kind of tensor with 16 = 4*4 components,called the energy-momentum-stress tensor because the additionalcomponents describe the energy and momentum as well as thestress.There's a second tensor describing a kind of curvature of space, andwhat GR says is that the curvature tensor is proportional to theenergy-stress-momentum tensor.So there are gravitational effects relating to momentum and tensionor compression as well as just energy; they are just usually tooweak to be noticed. Two long rods arranged parallel to each otherwill attract each other less, gravitationally, if under tension, for example.|With reducing eight to one?Doubtful.|Is tenser also a pun on ten, sir!?Evidently so! But your guess is as good as mine whether it'san intentional pun.Keith Ramsay === >[...]> It seems that many some readers of my post inferred that I was> complaining about the price of the textbook. My complaint was for not> including the worked out solutions to the odd numbered questions> either together with the textbook or on the CDROM which is already> included with the textbook.> I agree that academic textbooks are expensive and even more so if you> live in Canada. Since Canadian universities and colleges use the same> textbooks as in the US, the price of textbooks are even more expensive> because of the lower exchange rate for Canadian currency. For a> discrete mathematics course that I had taken recently, the course used> Rosen's Discrete Mathematics and Its Applications which costs $135> CDN plus the solutions manual for $55 and after tax, the amount was> over $200 (the US cost after currency conversion would have been even> more). Fortunately, some publishers charge a lower price for Canadian> purchasers otherwise textbooks would routinely cost over $150 CDN for> each textbook. Unfortunately, higher level textbooks are even more> expensive relative to the size of the books and publishers are less> likely to offer differential pricing to Canadian purchasers. A> introductory proof text that I had recently looked at was a small 400> page hardcover text that cost $133 CDN plus tax. I am not> knowledgeable about the academic book publishing business so I do not> have an informed opinion as to whether the textbook costs are> reasonable or not.> It looks like I will be shopping for secondhand textbooks.Well, the above prices _are_ to high.You can get reasonable books around 50 US$. Most of these books are betterthan the usual trash that is forced upon undergraduates.For instance Springer sells calculus books by Serge Lang in the rangeof 50-60 EUR. At least for US and Canada, Dover offers booksin the range of 10-20$. Then there is the AMS etc.I was well aware, that your complaint was not about the price as such;but still, the prices indicate that something is wrong.As mentioned before, publishers can sell these overpriced books becausethose who pay the price are not those who make the decisions aboutwhich text to adopt for a course.There is also the question if a textbook is really suitable for self-study.If I saw a book for a first year student that comes along with'solution manual', CD-ROM, where the main text perhaps has more than 1000pages etc., I would at least suspect that all this buzz is meant as a blindfor shortcomings of the main text.During a course, there are instructors and T.A.'s who can make the materialdigestible in spite of a poor book. During self-study you are on your own.Therefore it really helps to use the books in the library until you find abook that suits your needs.Marc === |> But it's possible to prove in ZF that the union of a countable family of|> countable subsets of w_1 is countable. If S_1, S_2, ... is a sequence of|> countable subsets of w_1, then they have least upper bounds a_1, a_2, ...|> in w_1, and the sequence a_1, a_2,... in turn has a least upper bound a.||How do we know that the sup of a_1,a_2,... is < w_1? For that matter|how do we even know a_1,a_2... are not equal to w_1?Sorry, my mistake here! In fact in the same model of Cohen's where heshows that the continuum is a countable union of countable sets, he showsthat aleph-1 is the sup of an increasing countable sequence of countableordinals.|Certainly you can reduce the statement to showing that a countable set|of countable ordinals is bounded above by a countable ordinal. In fact|you can even replace countable set of countable ordinals with|strictly increasing sequence of countable ordinals without too much|difficulty but I still don't see how to prove that the sup is strictly|less than w_1. And I've been told you can't prove it without AC,|though of course I can't justify that.Given a countable increasing sequence of ordinals a_1 < a_2 < a_3 <...with sup aleph-1, define (not needing choice!) the subsequenceb_1 < b_2 < ... where for each k, b_k is the first term in the a'ssuch that {u : u=b_j for j=b_j for j [snip]> Well, we do have someone who doesn't believe infinite sets exist, and goes>> so far as to say sets don't exist at all! That person is me.>> I don't believe in the Platonic realm or whatever, but I do assign greater>> degrees of realness to mathematical objects. Sets have my lowest>> realness rating.> But you do talk and think about them, right? Perhaps only in disguised form.> And when you do, you probably think about them *as if* they are fixed,> completed totalities? In that case, you are assuming lots of properties> about them....>Well, I try and think about them as little as possible. For me, sets arelinguistic constructs that are useful to me insofar as they give me aframework in which to talk about actual mathematical objects (actualmeans they have a high realness rating; I don't claim this is a precisenotion ;-)). In geometric contexts, most of the time I can talk about the geometricobjects without resorting to any set speak.I think when you suggest I think about sets in disguised form you areletting your bias for sets show. I would say that when I talk about setsthat I am talking about geometric objects in disguised form. So I thinkyou and I have a difference of opinion about what is disguising what.Continuing in the same vein, I don't see the relevance of pointing outthat I assume properties of sets. Sets are useful to me only if they haveproperties that approximate (in some sense) the behavior of geometricobjects. So I am really assuming lots of properties about them, wherethem does not refer to sets really. As an example, you seem to be chastising me for thinking of sets as fixedtotalities. Putting aside the fact that I am not really thinking ofsets as you may think I am, let me address this issue of fixedtotalities. Take the 2-sphere. I like to think of it as a fixed object. Where you might like to say, let S^2 be a sphere (the set of all points,etc...) and x be an element in S^2,my perspective, talking about the sphere in the first manner, as a setwith a fixed totality, is a perfectly good way to talk about it because itcaptures what I'm actually thinking (the second way). To only be able totalk about finite sets would be silly in this context. It would notcapture my idea of sphere.The point here is that I'm working in a specific context. I'm fine withother foundational theories, but not all of them will be useful to me. I'm not espousing that ZFC (or just ZF or whatever) is *the* foundation ofmathematics or anything of that sort. For me, that's irrelevant. > And, indeed, most mathematicians are not aware that they do exactly that:> assuming lots of things silently. They don't even care that they do.> But what can be done about it? Sigh.> I don't see what the problem is here. Of course I have to assume thatobjects I talk about have some properties. I don't see that because I'mnot interested in explaining my assumptions in the language of someaxiomatic theory this is a failing of some kind. The fact that you thinkit is a failing of mathematicians shows your own bias. === [snip] Well, we do have someone who doesn't believe infinite sets exist, andgoes>> so far as to say sets don't exist at all! That person is me.> I don't believe in the Platonic realm or whatever, but I do assigngreater>> degrees of realness to mathematical objects. Sets have my lowest>> realness rating.>> But you do talk and think about them, right? Perhaps only in disguisedform.> And when you do, you probably think about them *as if* they are fixed,> completed totalities? In that case, you are assuming lots of properties> about them.... Well, I try and think about them as little as possible. For me, sets are> linguistic constructs that are useful to me insofar as they give me a> framework in which to talk about actual mathematical objects (actual> means they have a high realness rating; I don't claim this is a precise> notion ;-)). In geometric contexts, most of the time I can talk about thegeometric> objects without resorting to any set speak.You got a point. (I smell a sense of irritation on your side; i apologize:-) )You are right, for geometry, it makes sense to view, say, 'spaces' as fixedtotalities.And, of course, i don't know how you talk about your subject to students.[snip]> The point here is that I'm working in a specific context. I'm fine with> other foundational theories, but not all of them will be useful to me.> I'm not espousing that ZFC (or just ZF or whatever) is *the* foundation of> mathematics or anything of that sort. For me, that's irrelevant.That is very good, and very interesting.People doing foundations should be interested in what you do, and inexplicitizingthe assumptions you actually use / need in this kind of geometry.But are they? And are geometers themselves interested in making theseassumptionsmore explicit?I know most mathematicians are not; and when they teach their subject tostudents,they simply continue the tradition: ZFC or an informal version of it,without thinking further.In that sense, the math culture has stopped questioning the basics.Doesn't that worry you? It does worry me. Because i think it is this thatdistractsyoung people from a study or a career in math. And it is also not a goodsign,in general, for the future of a science.Herman Jurjus === > [snip] _Pace_ Wigner, what's unreasonable isn't that correct>> mathematics correctly understood and applied can be effective>> in understanding the world, it's that Cargo Cult Mathematics>> seems to actually work sometimes (whereas Cargo Cult Science>> hardly ever does). Lee Rudolph> what does cargo cult mathematics mean?> KevinYork 1985, ISBN 0-393-01921-7). <3f314280$7$fuzhry+tra$mr2ice@news.patriot.net> X-Cise: tanbanso@iinet.net.auX-CompuServe-Customer: YesX-Coriate: admin@interspeed.co.nzX-Ecrate: tanandtanlawyers.comX-Punge: Micro$oft === at 09:57 AM, kevin.roberge@umit.maine.edu (Kevin Roberge) said:>what does cargo cult mathematics mean?Dirac Delta Function. Renormalization. Formal power series that maynot converge.-- Shmuel (Seymour J.) Metz, SysProg and JOATReply to domain Patriot dot net user shmuel+news to contact me. Do not replyto spamtrap@library.lspace.org === >So are you saying that the Y-chromosome that God made for Jesus would>>somehow be different than the one he made for Adam?> Why would you ask such a silly question? There isn't nearly enough> information in scripture to draw that sort of conclusion. Odds favor> the conjecture that they were different, of course, unless you propose> that Jesus and Adam were identical twins.> Never mind all that. Do you propose that Adam existed?> Well, assuming it would make the thread even funnier. ;+)> Some claim that Jesus = God. Which means Mother of Jesus = Mother of God. > So, Jesus' Y chomosome would be God's. However, AFAICT, Nobody says Adam> had God's Chromosomes. God likely made Adam's genes like he made> everything else's -- complete with a billion-year history.Why do you assume that Jesus and Adam had different Y-chromosomes?After all, if Jesus was made directly by God and Adam was madedirectly by God shouldn't they both have the same Y-chromosome? ;) === > So are you saying that the Y-chromosome that God made for Jesus would> somehow be different than the one he made for Adam?> Why would you ask such a silly question? There isn't nearly enough> information in scripture to draw that sort of conclusion. Odds favor> the conjecture that they were different, of course, unless you propose> that Jesus and Adam were identical twins.> I made the fairly simple statement that scripture calls Christ the> only _begotten_ son of God, while distinctly calling others than> Christ sons of God. This clearly implies a distinction.They don't have to be identical twins to have the same Y-chromosome.All they need to have is the same father. Since both Adam and Jesuswere supposedly made by God then it would follow that they wouldboth have the same Y-chromosome. ;) === > Actually 1 slug = 32 (lbm), give or take a few ounces. It's> either a numerical accident or by planning by the appropriate> Standards Committee(s) long ago that the force exerted by> 1 lbm in the Earth's gravitational field is exactly 1 lbf.No standards committee has ever officially defined a pound force. In 1995, the best NIST could do is to give us a qualified definition,with a big if depending on the choice of a standard acceleration offree fall (NIST generally uses the one which is official for definingthe kilogram force, something that was done not so very long ago, justa little more than a century ago in 1901, by the CGPM).The force exerted by 1 lb (the symbol used by the experts such as NISTand NPL, the U.K. standards agency; it is only the recentbastardization which needs to distinguish itself by using the symbollbf) in Earth's gravitational field is somewhere between 15.93 ozf and16.04 ozf. There is no place at all on earth where the force exertedby 1 lb is always exactly 1 lbf or even always 1.0000 lbf expressedto that precision, because the local acceleration of gravity varieswith time, being dependent on such things as the relative positions ofthe sun and moon wrt earth.Gene Nygaardhttp://ourworld.compuserve.com/homepages/Gene_Nygaard/ weight.htmThere is another type of measure that is also very ancient and that is the measure of mass. . . . As time passed, each nation and region developedits own standard masses against which unknown massescould be compared. The chief such unit is calledpound in English, from a Latin word meaning a weight. Isaac Asimov Realm of Measure,l960 === Cut<>> No standards committee has ever officially defined a pound force.> In 1995, the best NIST could do is to give us a qualified definition,> with a big if depending on the choice of a standard acceleration of> free fall (NIST generally uses the one which is official for defining> the kilogram force, something that was done not so very long ago, just> a little more than a century ago in 1901, by the CGPM).>> The force exerted by 1 lb (the symbol used by the experts such as NIST> and NPL, the U.K. standards agency; it is only the recent> bastardization which needs to distinguish itself by using the symbol> lbf) in Earth's gravitational field is somewhere between 15.93 ozf and> 16.04 ozf. There is no place at all on earth where the force exerted> by 1 lb is always exactly 1 lbf or even always 1.0000 lbf expressed> to that precision, because the local acceleration of gravity varies> with time, being dependent on such things as the relative positions of> the sun and moon wrt earth.>That's right Gene: It's the inertia - the _ratio_ of 1 lbf to theacceleration of free fall; that is constant, and a measure of mass that is_constant_; because the acceleration of free fall varies with time, beingdependent on such things as the relative positions of the sun and moon wrtearth. === In sci.math, Gene Nygaard:>> Actually 1 slug = 32 (lbm), give or take a few ounces. It's>> either a numerical accident or by planning by the appropriate>> Standards Committee(s) long ago that the force exerted by>> 1 lbm in the Earth's gravitational field is exactly 1 lbf.> No standards committee has ever officially defined a pound force. > In 1995, the best NIST could do is to give us a qualified definition,> with a big if depending on the choice of a standard acceleration of> free fall (NIST generally uses the one which is official for defining> the kilogram force, something that was done not so very long ago, just> a little more than a century ago in 1901, by the CGPM).> The force exerted by 1 lb (the symbol used by the experts such as NIST> and NPL, the U.K. standards agency; it is only the recent> bastardization which needs to distinguish itself by using the symbol> lbf) in Earth's gravitational field is somewhere between 15.93 ozf and> 16.04 ozf. There is no place at all on earth where the force exerted> by 1 lb is always exactly 1 lbf or even always 1.0000 lbf expressed> to that precision, because the local acceleration of gravity varies> with time, being dependent on such things as the relative positions of> the sun and moon wrt earth.but I for one would have at least thought that 1 lbf would havebeen exactly the force exerted by 1 lb, assuming a certain valueof g. Then again, it's clear SI is far more coherent on thisparticular point anyway, although I have identified an inaccuracywhich is probably so minute it's meaningless. However, hasanyone looked into it?Basically, the acceleration depends on a unit of time:1 m/s/s. This unit of time is being measured in a curvedgrav field, which varies. While the variation is extremelysmall, there is one, in theory -- and I'm wondering ifit's detectable at all on a lab bench (Hafele and Keatingtook a trip around the world with cesium-beam clocks anddid detect it, so it's doable in theory).It's also far less than the 0.4% g variation anyway so Iam probably worrying too much.... :-)[.sigsnip]-- #191, ewill3@earthlink.netIt's still legal to go .sigless. === >In sci.math, Gene Nygaard>>:>> Actually 1 slug = 32 (lbm), give or take a few ounces. It's> either a numerical accident or by planning by the appropriate> Standards Committee(s) long ago that the force exerted by> 1 lbm in the Earth's gravitational field is exactly 1 lbf. No standards committee has ever officially defined a pound force. >> In 1995, the best NIST could do is to give us a qualified definition,>> with a big if depending on the choice of a standard acceleration of>> free fall (NIST generally uses the one which is official for defining>> the kilogram force, something that was done not so very long ago, just>> a little more than a century ago in 1901, by the CGPM). The force exerted by 1 lb (the symbol used by the experts such as NIST>> and NPL, the U.K. standards agency; it is only the recent>> bastardization which needs to distinguish itself by using the symbol>> lbf) in Earth's gravitational field is somewhere between 15.93 ozf and>> 16.04 ozf. There is no place at all on earth where the force exerted>> by 1 lb is always exactly 1 lbf or even always 1.0000 lbf expressed>> to that precision, because the local acceleration of gravity varies>> with time, being dependent on such things as the relative positions of>> the sun and moon wrt earth.>>but I for one would have at least thought that 1 lbf would have>been exactly the force exerted by 1 lb, assuming a certain value>of g. Yes, that's what it is, of course. It's just that no standardscommittee has ever bothered to set a *standard* value to be used bythe people over whom that standards committee has jurisdiction--nonational or international standards laboratory, no professionalorganization, no national legislature, etc.The most common values used for that g_n, the standard acceleration offree fall, include 9.80665 m/s (which is official for defining gramsforce and kilograms force), 32.16 ft/s, 386.1 in/s, and otherspractically indistinguishable, in almost all applications in the realworld, from the first such as 32.174 ft/s and 1 lbf/1 lb = 4.44822N/0.45359237 kg or approximately 9.806646... m/s. Many textbooksalso use 32.2 ft/s and even 32 ft/s, though I haven't encounteredany that clearly treat this as a precise definition.>Then again, it's clear SI is far more coherent on this>particular point anyway, SI is exactly as clear on this point as the absolute fps system ofunits is, with a poundal defined as exactly 1 lbft/s. It issomething totally immaterial in either of these systems. In neitherof these systems does a standard acceleration of free fall serve anypurpose whatsoever.The situation is also different for the non-SI grams force andkilograms force, which are officially defined, since the CGPM adoptedfor this purpose in 1901 a standard acceleration of gravity equal to980.665 cm/s.Gene Nygaardhttp://ourworld.compuserve.com/homepages/Gene_Nygaard/= === Cut<>> Yes, that's what it is, of course. It's just that no standards> committee has ever bothered to set a *standard* value to be used by> the people over whom that standards committee has jurisdiction--no> national or international standards laboratory, no professional> organization, no national legislature, etc.>That would be pretty stupid don't you think? The acceleration of free fallvaries at various locations on Earth; for various reasons: Mainly dependingon the strength of gravity at that location and the centrifugal effect dueto Earth's rotation._Tables_ have been prepared showing this acceleration; as measured atnumerous locations. There is no standard acceleration of free fall: It iswhat it is at those locations because it depends on the strength of gravityand the centrifugal effect due to Earth's rotation there.No national or international standards laboratory, no professionalorganization, no national legislature, or anybody else can change theacceleration of free fall: that's up to mother nature!> The most common values used for that g_n, the standard acceleration of> free fall, include 9.80665 m/s (which is official for defining grams> force and kilograms force), 32.16 ft/s, 386.1 in/s, and others> practically indistinguishable, in almost all applications in the real> world, from the first such as 32.174 ft/s and 1 lbf/1 lb = 4.44822> N/0.45359237 kg or approximately 9.806646... m/s. Many textbooks> also use 32.2 ft/s and even 32 ft/s, though I haven't encountered> any that clearly treat this as a precise definition.>Woe be it when they start doing this: Those are just convenientapproximations: Close enough for the practical applications to which theypertain.National and international standards laboratories and professionalorganizations, and national legislatures have banded together and adopted a_standard weight_; the weight of the kilogram artifact that is stored forsafe keeping at the international archives in Sevres France.This artifact serves as the standard for weight all over the civilizedworld, and accurate copies of it have been distributed to all membercountries - including the U.S. - who use it as the basis for weightmeasurements.The kilogram is called a _unit_ of mass, because originally it was a cubicdecimeter of pure water at its maximum density; with a scale-weight that wasnumerically; _exactly_ equal to the acceleration of free fall at thelocation of the scale on which it was weighed; so that its weight [w]divided by the acceleration at which it will free fall [g] equals One!It's taking a while for science to realize that this ratio [w/g] is equal tothe ratio of the net force [f] to the forced displacement [s/t] thatconstitutes inertia; the property of an object that requires the applicationof an external force in order to change the object's velocity. That akilogram is a unit of inertia, and a measure of mass may take a while(;^)That a kilogram is a measure of sluggishness; and/or disinclination toactivity may take even longer(;^) === >> I must respectfully disagree with the seeming consensus of the> mathematicians whose analyses I scanned. The seeming paradox has littleto> do with the specific distributions assumed for the source of the pairs.It is resolved in all cases by inclusion of the boundary cases in the> calculation of expected gain over any finite series.>> I haven't thought it through completely, but it would seem that awinning> strategy would be to switch in every case in which you observe a valueless> than the maximum value you have previously observed, otherwise to stickwith> your first choice.>> Of course if you are told a maximum bound ahead of time there is noproblem.> Always switch unless you see that value.> knowing the bound IS having knowledge of the distribution!>> HercOf course. But the resolution of the paradox does not depend on knowing abound, or on any reasoning about any particular kinds of distribution. Theparadox arises because of the conflict between the provable impossibility ofoverall gain from unconditional switching, and a seemingly valid calculationwhich says one will indeed gain from unconditional switching. To defeat theparadox, one need only recognize that the estimation of benefit fromunconditional switching must also include the guaranteed loss at the(typically unknown) upper bound of the values encountered in any finiteseries of trials.In an infinite series of trials with no finite upper bound, switching mightbe said to improve the rate of gain, but your expectation in any case iseither infinite or undefined depending on which aspects of the picture youwant to quibble about, so there is no paradox to be worried about in thefirst place...I mentioned knowing the bound only in context with explicating theconditions under which one could actually gain by a conditional switchingstrategy.Bill === Hey James,Sorry, I forgot to tell you that it's under renovation now (tillaround the 11th of August). So perhaps, some entries do not work.Math Observer === > Hey James,> I gave an HONEST suggestion. I thought that your elementary proof of> the FLT could perhaps be propagated here in HK as well (with so many> young math enthusiasts around!).> Math Observer> PS: I'm an HK Math Observer (and I don't know the guys you> mentioned!).> PPS: I am simply interested in making the amateurs here do something> useful (discuss and scrutinize your elementary proof (?) using> elementary methods).> You're replying to the imposter. In any event, it's worth my saying> again that I went to the link you gave and tried to post.> Here's a copy of what I said in my previous reply:> How about you do me a favor and post the following there and post back> if there are any interesting comments?Well there's a problem that someone pointed out with what I had, whichluckily is not a big deal. More below...> which is> P(0)/f^2 = u^2 (b_3 w_1 w_2 x + u f) = u^2(3x + uf)> proving that w_1 w_2 must equal 1, if f is coprime to 3, which leaves> b_3 = 3.Yup, and I should have remembered that fact.> Essentially objections to how f^2 divides off now come down to> claiming that the w's are functions of m, but consider that w_1 w_2 => 1, when m=0, if f is coprime to 3.> But that was an arbitrary choice, so let f=3.> Now w_1 w_2 = 3^{2/3} WITHOUT REGARD TO m.OOPS!!! Now w_1 w_2 is still coprime to 3, but w_3 = 3 WITHOUT REGARDTO m, which follows from P(0)/3^2 = u^2 (b_3 w_1 w_2 x + 3u) = u^2(3x + uf)as that 3 factor of 3u has to get out of there someway and it can't bethrough w_1 w_2.> That is, the w's are now all constant with regard to m and have the> same value no matter what the value of m is.It's not a big deal as that is still true.> Therefore, the factorization is> P(m)/f^2 = (m^3 f^4 - 3m^2 f^2 + 3m) x^3 - > 3(-1+mf^2 )x u^2 + u^3 f => (b_1 x + u)(b_2 x + u)(b_3 x + uf)which still works with f=3, as then all that happens is that last fcan divide through> where you'll notice that the b's are algebraic integers with m=1,> f=sqrt(2), but that's a special case as generally they are not, which> shows a problem with the ring of algebraic integers.> I've found the Ring of Objects which includes the ring of algebraic> integers, and does not have this problem, as the b's are all included> in it.> The Ring of Objects is the set of all numbers where -1 and 1 are the> only members that are both a unit, i.e. factor of 1, and an integer,> where no non-unit member is a factor of any two integers that are> coprime.That's a nifty definition that's extremely powerful.> That definition and more is linked to from my primary website http://groups.msn.com/AmateurMath> where you can also find information on my other math research. James Harris === > That's a nifty definition that's extremely powerful.Nifty or not nifty, please post it there, James.(Math forum works --- and so is its LateX stuff)Math Observer === [snip]> My hope is that these issues can be resolved to some extent through> Usenet's strength: Discussion.> Ah, the triumph of hope over experience.[snip]> James Harris === > That's a nifty definition that's extremely powerful.>> Nifty or not nifty, please post it there, James.He is not yet finished. All you see here are just his drafts. === > The Ring of Objects is the set of all numbers where -1 and 1 are the> only members that are both a unit, i.e. factor of 1, and an integer,> where no non-unit member is a factor of any two integers that are> coprime.You forgot to define operations here.Without operations it's just a set of numbers, not a ring.Thus your whole FLT proof is invalid. === > That's a nifty definition that's extremely powerful.> Nifty or not nifty, please post it there, James.> (Math forum works --- and so is its LateX stuff)> Math ObserverI've posted using the directions given at the site for the version ofLaTex used by the site.Hopefully tomorrow it will display properly.In any event, it is readable, even with the formatting code.James Harris === >That's a nifty definition that's extremely powerful.>>Nifty or not nifty, please post it there, James.>>(Math forum works --- and so is its LateX stuff)>>Math Observer> I've posted using the directions given at the site for the version of> LaTex used by the site.> Hopefully tomorrow it will display properly.> In any event, it is readable, even with the formatting code.> James HarrisI find it interesting that no one there had a clue what you were talking about.-- Will Twentyman === > If R is a noncomutative integral domain and M is a R-module. How do you> prove that Tor(M) = { m in M | r m = 0 for some r in R} is a submodule of> ^^^^^^> nonzero! :-)> M??> I don't think you do :-(Robin is correct as usual. But oddly enough, exactly the same error occurs in an exercise in Godement's Algebra (Hermann 1968), exercise 11.11: Let M be a left module over a ring K. a) For each x in M, the annihilator of x is defined to be the set of all lambda in K such that lambda x = 0.... b) Suppose that K is an integral domain. Show that the elements x of M whose annihilator is not {0} form a submodule T of M.... I checked - he does not assume rings or integral domains are commutative.Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === Can anybody give me a more intuitive description of the total derivative?Not the definition, please.TIA,Lurch === > -- I'm CanSpice in that thread and the person on the other side of the > argument is Aylutar) about trying to prove the old adage that if you had > an infinite number of monkeys typing on an infinite number of typewriters > for an infinite amount of time, you would produce the works of > Shakespeare.Actually, this theory has never been tested due to lack of research funds.The closest approximation was an experiment with three-quarters of aninfinite number of monkeys, who typed: To be or not to be; that is the question. Whether 'tis nobler in the mind to suffer The slings and arrows of outrageous fortune Eeepps jksaagj effauyp dsajfjkd eepdoosI believe, however that Robert Wilensky has argued that we have a perfectlygood *natural* experiment: The hypothesis is that an infinite number ofmonkeys at an infinite number of keyboards will eventually produce the completeworks of Shakespeare; our experience of Usenet refutes this hypothesisrather definitively. It's also been observed (I forget by whom) that if an infinite number ofmonkeys are given an infinite number of typewriters, then with probabilityone at least one monkey will figure out how to beat the monkeys around itto death with its typewriter.Steven E. Landsburgwww.landsburg.com/about2.html === > |>Some countable ordinals have a finite desciption in English> |>(abbreviated hereon to FDIE).> The restriction to countability isn't strictly necessary, of course.> |[...]> |> |>This raises the question of whether the FIRST countable ordinal which> |>has no FDIE has a FDIE.> |> |Sounds to me like the proof that each natural number is an interesting > |number...> I agree. I think the possibility of describing a mathematical object> like an ordinal (by way of a well-ordering on the natural numbers, say)> is intimately related to its holding an interest for us, enabling it to be> distinguished from among the closely related objects by means of a> finite amount of pointing out. I would call it a strengthening of the> paradox of the first uninteresting natural number, because while one> can imagine that the natural numbers are all at least microscopically> interesting, it's not so easy to imagine from a realist perspective that> ALL ordinals (going up to ones of arbitrarily large cardinality) continue> to have some positive interest to them.> The paradox is that these concepts are slippery enough not to be> able to reflect back on themselves in such a way.> Keith Ramsay> It sounds to me like these are simply inconsistent self-referential definitions. In essence, each of them boils down to a description phrase like, an object that is not described by this description. An inconsistent definition isn't a very interesting paradox; it's just nonsense. === >> |>Some countable ordinals have a finite desciption in English> |>(abbreviated hereon to FDIE).>> |>This raises the question of whether the FIRST countable ordinal which> |>has no FDIE has a FDIE.> |> |Sounds to me like the proof that each natural number is an interesting> |number...>> I would call it a strengthening of the paradox of the first> uninteresting natural number, because while one can imagine that the> natural numbers are all at least microscopically interesting, it's not> so easy to imagine from a realist perspective that ALL ordinals (going> up to ones of arbitrarily large cardinality) continue to have some> positive interest to them.>> The paradox is that these concepts are slippery enough not to be> able to reflect back on themselves in such a way.>Similar to the first non-recursively enumerable ordinal?Also reminds me of the ordinal number of all ordinals. === >Some countable ordinals have a finite desciption in English>(abbreviated hereon to FDIE). For example 'the first countable>ordinal which is greater than any finite ordinal' is a FDIE of a>countable ordinal. So is 'the first countable ordinal which is>greater than any finite ordinal raised to the power of the first>countable ordinal which is greater than any finite ordinal'.>>However, not all countable ordinals do have a FDIE. The reason for>this is because the number of FDIEs is countable (quite>straightforwardly, the set of finite combinations of a finite set of>symbols is countable); On the other hand, the set of countable>ordinals is UNcountable.>>This raises the question of whether the FIRST countable ordinal which>has no FDIE has a FDIE.>>If it DOES, this would contradict the fact that it's the first>countable ordinal which does NOT have a FDIE.>>If it DOESN'T, this would contradict the fact that I've just give a>FDIE of it, namely: 'The first countable ordinal which does not have a>FDIE'.The resolution of the paradox is to note that the phraseFDIE is unacceptably vague. If you give a precisedefinition of what strings of English words constituteFDIE's of ordinals (together with an explanation ofexactly which ordinal is defined by a FDIE) then youfind that smallest ordinal that has a FDIE does notqualify as a FDIE.************************David C. Ullrich === > The resolution of the paradox is to note that the phrase> FDIE is unacceptably vague. If you give a precise> definition of what strings of English words constitute> FDIE's of ordinals (together with an explanation of> exactly which ordinal is defined by a FDIE) then you> find that smallest ordinal that has a FDIE does not> qualify as a FDIE.> ************************> David C. UllrichOkay, suppose we have a precise definition D of what strings inEnglish constitute FDIEs of ordinals.Consider the string:the smallest ordinal which is not in the set of ordinals which aredescribed by FDIEs under definition DSince D is a precise definition it must include the above string.If it DOES include the above string we're back at the paradox.Richard Clark === The resolution of the paradox is to note that the phrase>> FDIE is unacceptably vague. If you give a precise>> definition of what strings of English words constitute>> FDIE's of ordinals (together with an explanation of>> exactly which ordinal is defined by a FDIE) then you>> find that smallest ordinal that has a FDIE does not>> qualify as a FDIE. ************************ David C. Ullrich>>Okay, suppose we have a precise definition D of what strings in>English constitute FDIEs of ordinals.>>Consider the string:>>the smallest ordinal which is not in the set of ordinals which are>described by FDIEs under definition D>>Since D is a precise definition it must include the above string.Huh??? That doesn't follow at all.>If it DOES include the above string we're back at the paradox.Yes, if the above _is_ an FDIE of an ordinal. This is no problem, until you _give_ a precise definition of FDIE of anordinal such that the above _is_ an FDIE of an ordinal.Exactly what definition of FDIE of an ordinal are you using?>Richard Clark************************David C. Ullrich === |It sounds to me like these are simply inconsistent self-referential |definitions. In essence, each of them boils down to a description |phrase like, an object that is not described by this description. An |inconsistent definition isn't a very interesting paradox; it's just |nonsense.Well, why didn't we all think of that earlier? :-)Everybody who looks at paradoxes, involving self-reference like these do,concludes that there's something wrong with the definitions and that ithas something to do with their being circular. That's not what people areafter when they spend more than a little bit of time trying to resolvethem. That's just the starting point. One might hope, for example, that anexplanation for why the definitions are wrong would give some kind ofcriterion for when circularity of various kinds is okay and when it isn't.Saying you know precisely why a problem has occurred but are unable togive a reasonable rule for avoiding the problem in the future is a littledubious.Impredicative definitions are an example. There have been people whothought that when you define a set, it should be a set composed of elementsthat you could have defined before defining the set itself. Otherwise, theysay, there's a kind of invalid circularity.The consequences for mathematics are substantial because the definition ofthe real numbers is impredicative. By the Dedekind cut construction, a realnumber is given by a collection of rational numbers (satisfying someconditions like being downward closed). Such a set of rationals is given as {r : r satisfies ...}where we can refer to just about anything in .... So this kind ofalleged circularity exists, because ... could talk about the real numberline and its properties.On the other hand, there have been lots of people with the point of viewthat definitions like this are okay, because the reals are all therealready, and by making a definition we are merely selecting from outof a pre-existing domain.A thorough unravelling of the paradox should help us to see whether thiskind of circularity or apparent circularity is valid, or whether it justmakes the same mistake as the paradox does but inadvertently avoids runninginto a direct contradiction. That's the kind of thing that makes suchparadoxes interesting to some people.Keith Ramsay === >> The resolution of the paradox is to note that the phrase>> FDIE is unacceptably vague. If you give a precise>> definition of what strings of English words constitute>> FDIE's of ordinals (together with an explanation of>> exactly which ordinal is defined by a FDIE) then you>> find that smallest ordinal that has a FDIE does not>> qualify as a FDIE. ************************ David C. Ullrich>>Okay, suppose we have a precise definition D of what strings inEnglish constitute FDIEs of ordinals.>>Consider the string:>>the smallest ordinal which is not in the set of ordinals which are>described by FDIEs under definition D>Since D is a precise definition it must include the above string.> Huh??? That doesn't follow at all.> Well, I guess that depends on what the precise definition of 'precisedefinition' is ... === > Nonsense, just take the probability of an event to be> its Lebesgue measure. Try some post-1850 mathematics> for a change. Game over.> Aw, Wade, you're right but also that's kind of harsh,> considering that a significant percentage of posts have> no math content whatsoever, posts in this thread being> among them.Perhaps, but I hold the mathematical posts to a higher standard.> By the way, have you found a job yet?This doesn't ring a bell with me. Can you remind me what has prompted your question here? === > Perhaps, but I hold the mathematical posts to a higher standard.How silly of me.I thought you were taking a shot at me,after the fact, in sympathy with your colleague.I say after the fact, because in this thread,Prof. Israel had explained, succinctly, the errorof my ways.> By the way, have you found a job yet?> This doesn't ring a bell with me. Can you> remind me what has prompted your> question here?You took your shot. Tit for tat. === > Perhaps, but I hold the mathematical posts to a higher standard.> How silly of me.> I thought you were taking a shot at me,> after the fact, in sympathy with your colleague.> I say after the fact, because in this thread,> Prof. Israel had explained, succinctly, the error> of my ways.> By the way, have you found a job yet? This doesn't ring a bell with me. Can you> remind me what has prompted your> question here?> You took your shot. Tit for tat.My shot (your term) was based on the mathematics. Your shot is from the bizarro world. === >> Suppose that you flip a coin infinitely many times. What is the>> probability that you get all heads? Zero. Does that mean that it's ^^^^>> impossible to get all heads? No,...> Yes.>> you get _some_sequence, and any given sequence is just as likely as any>> other.> Although, a priori, any_finite_sequence of a given length is as likely as> any other, I claim: When flipping a fair coin, an infinite sequence of> heads is impossible, theoretically. Such a sequence, violates the axioms> of probability. If an event has non-zero probability it must occur in ^^^^^^^^> infinitely-many trials with probability 1. Granted, though, there may be> arbitrarily long sequences, beginning HHH...HT... As you write:Pay attention, Nat.Phil === > http://mr-31238.mr.valuehost.co.uk/assets/Flash/psychic.swf Well... With 40, I decided to do: 40 + 4+0 = 44, and the symbol> for 44 didn't appear...>> David Bernier>But with 40, this becomes 40 - (4 + 0) = 36 and the symbol for 36 does infact appear === Your skills are worth a lot more than you think. You should register yourselfand your math skills in the Design /Engineering / Technical professionaldatabase of Invent2win Competitive Products LLC, a (mass) product developmentcompany. Professionals earn $200,000- $2,000,000 per project .89 NOT $70 - $100thousand dollars per year.You have learned, now it's time to earn! No need to leave your current job.Contract with us!Learn more @http://invent2win.com/careers/contract_program.asp === >For continuous data f(x) on [a,b], we can calculate the mean or>average value as>A = 1/(a-b) int{a,b} f(x) dx>My question is can we calculate the variance of a continuous>function as>>1/(a-b) int{a-b} (f(x) - A)^2 dxI assume you mean 1/(b-a) int_a^b (f(x) - A)^2 dx.This is the variance of f(X) where X is a random variable with uniform distribution on [a,b].>For N discrete data points, we can divide by either N or N-1 to>get biased or unbiased estimator, but is there this distinction in>continuous case?I'm not sure what you mean by continuous data here. I think you mayhave to explain the situation you have in mind. Where does the functionf come from?Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === > Carol Rees schrieb: I need to solve the sum of 1 + 2^2 +3^2 +4^2+......n^2 as part of a> statistics problem. It seems simple but it doesn't seem to fit in with the> usual solutions for arithmetic or geometric progression.> look at http://www.research.att.com/~njas/sequences/ and type in a few members> of your series. You get n(n+1)(2n+1)/6.> hth> KlausThat's very interesting because I have just been interested in somethingvery similar. Lets say you have a series of numbers (lets call it A) 1, 4, 9, 16, 25, 36, 49, 64, 81 ...just as Carol Rees talked about. Now you have a second series of numbers(call this B) x+1, x+4, x+9, x+16, x+25, x+36, x+49, x+64, x+81 ... wherex is some positive integer.These are two totally regular (aren't they) series of numbers. Now how can Idetermine the set of numbers which are common to A and B? The intersection ofset A and set B. === X is not a random variable. Better notation would be f(t) where t istime. If we have N discrete points f1, f2, ..., fN, we can estimate thevariance of this series by Var = 1/(N-1) sum{i=1,N} (fi - Mean)^2This is the usual unbiased estimator. Now consider the continuous functionf(t) on [a,b], and I want to measure how wavy or how spread out thefunction is so I want to know if we can calculate the variance as Var = 1/(a-b) int(a,b) (f(t) - Mean)^2 dt> I'm not sure what you mean by continuous data here. I think you may> have to explain the situation you have in mind. Where does the function> f come from? === >X is not a random variable. Better notation would be f(t) where t is>time. If we have N discrete points f1, f2, ..., fN, we can estimate the>variance of this series by> Var = 1/(N-1) sum{i=1,N} (fi - Mean)^2>This is the usual unbiased estimator. Now consider the continuous function>f(t) on [a,b], and I want to measure how wavy or how spread out the>function is so I want to know if we can calculate the variance as> Var = 1/(a-b) int(a,b) (f(t) - Mean)^2 dtThe unbiased estimator of _what_? You can't have an unbiased estimatorunless there's some underlying probability model.If you have a collection of random variables X_1,...,X_n whose probability distribution depends on some unknown parameters, an unbiased estimator of some parameter q is Q(X_1,...,X_n)(a function of the given random variables) such that E[Q(X_1,...,X_n)] = q for all values of the unknown parameters.In the case of your N points f1,...,fN, these are assumed to be independent random variables with the same unknown probability distribution.But in the case of your continuous function f(t), what kind ofdistribution is this supposed to be taken from? You certainlycan't assume that f(t) for different t's are independent, becausethen (except in the trivial case where f(t) is almost surely constant)f(t) won't be a measurable function and the integral won't exist.Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === > X is not a random variable. Better notation would be f(t) where t is> time. If we have N discrete points f1, f2, ..., fN, we can estimate the> variance of this series by> Var = 1/(N-1) sum{i=1,N} (fi - Mean)^2> This is the usual unbiased estimator. Now consider the continuous function> f(t) on [a,b], and I want to measure how wavy or how spread out the> function is so I want to know if we can calculate the variance as> Var = 1/(a-b) int(a,b) (f(t) - Mean)^2 dtThis is the mean of the function (f(t)-mu)^2, which is thedefinition of the variance. As with the discrete case, you canprove that it's equal to E[f(t)^2] - Mean^2.So long as f(t) is well-behaved I don't think there's anyproblem with defining this, which is an estimator of a statisticover the uncountable number of samples {f(t): t in [a,b]}. - Randy === >That's very interesting because I have just been interested in something>very similar. Lets say you have a series of numbers (lets call it A) >1, 4, 9, 16, 25, 36, 49, 64, 81 ...>just as Carol Rees talked about. Now you have a second series of numbers>(call this B) x+1, x+4, x+9, x+16, x+25, x+36, x+49, x+64, x+81 ... where>x is some positive integer.>These are two totally regular (aren't they) series of numbers. Now how can I>determine the set of numbers which are common to A and B? The intersection of>set A and set B.I don't know how this got into the variance thread. Anyway, it really has very little to do with Rees's question. You just want to solve theDiophantine equation a^2 = x + b^2 for a and b. Write this as(a-b)(a+b) = x, look for ways to factor x such that both factors areodd or both are even, and you have your answer.Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israelUniversity of British ColumbiaVancouver, BC, Canada V6T 1Z2 === > In the case of your N points f1,...,fN, these are assumed to be> independent random variables with the same unknown probability> distribution.Yes, that was precisely what I had in mind: E(fi) = mu and Var(fi) = s^2 forall i.For estimating the mean, we compute 1/N sum(i=1,N) fi for N samples f1 to fN.I had thought this was related to the notion of average value of a continuousfunction given by 1/(a-b) int{a,b} f(t) dt (that everybody learns in calculusI), but maybe not since f(t) here is deterministic??Actually what I have in mind for f(t) is a continuous time stochastic process(a function of possibly correlated Wiener processes), and so f(t) denotes onesample path. I'm trying to find a way of measuring how spread out the _path_f(t), a> In the case of your N points f1,...,fN, these are assumed to be>> independent random variables with the same unknown probability>> distribution.>Yes, that was precisely what I had in mind: E(fi) = mu and Var(fi) = s^2 for>all i.>For estimating the mean, we compute 1/N sum(i=1,N) fi for N samples f1 to fN.>I had thought this was related to the notion of average value of a continuous>function given by 1/(a-b) int{a,b} f(t) dt (that everybody learns in calculus>I), but maybe not since f(t) here is deterministic??It's related in the sense that both are integrals, but the situation issomewhat different.>Actually what I have in mind for f(t) is a continuous time stochastic process>(a function of possibly correlated Wiener processes), and so f(t) denotes one>sample path. I'm trying to find a way of measuring how spread out the _path_>f(t), a infinity.Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === Under AC, of course, does there exist an algortihm which develops a well-ordering of the reals (not necessarily in finite time) and which has the property that, given any two real numbers, it determines in finite time which of the two is no greater than the other under this ordering?My guess is no. Such an algorithm would need to take countably many steps. Infinitely many of the steps must order an uncountable subset of R in finite time. If one could do that, one could well-order R without choice [not sure about this step]. Have I just answered my own question?-- Stephen J. Herschkorn herschko@rutcor.rutgers.edu === > Under AC, of course, does there exist an algortihm which develops a> well-ordering of the reals (not necessarily in finite time) and which> has the property that, given any two real numbers, it determines in> finite time which of the two is no greater than the other under this> ordering?Exactly what do you mean by given any two real numbers?On the face of it, it seems like only equality would be a problem, no? === * Stephen J. Herschkorn> Under AC, of course, does there exist an algortihm which develops a> well-ordering of the reals (not necessarily in finite time) and which> has the property that, given any two real numbers, it determines in> finite time which of the two is no greater than the other under this> ordering?I am not sure if I understand the question. How do you definealgortithm? Most definitions include the condition that it has toterminate in finite time. What does it mean for an algorithm, or acomputer program, to terminate in infinite time? (How do youdistinguish such a program from, say WHILE (TRUE) DO NOTHING.-- Jon Haugsand === JH:>* Stephen J. Herschkorn>> Under AC, of course, does there exist an algortihm which develops a> well-ordering of the reals (not necessarily in finite time) and which> has the property that, given any two real numbers, it determines in> finite time which of the two is no greater than the other under this> ordering?I am not sure if I understand the question. How do you define>algortithm? Most definitions include the condition that it has to>terminate in finite time. What does it mean for an algorithm, or a>computer program, to terminate in infinite time? (How do you>distinguish such a program from, say WHILE (TRUE) DO NOTHING.>An algorithm is a finitely-specified list of steps. Such an algorithm would define a well-ordering S on the reals. The algorithm would take as input two reals x and y (specified as you wish) and, in finite time, return as an output either (x,y) in S or (y,x) in S.I see that the specification of x and y may present problems. For example, if we wish to specify a real by a decimal expansion, we may not even be able to specify it in finite time.What I am trying to do is construct a well-ordering of reals, whose existence the axiom of choice implies.NS:>Exactly what do you mean by given any two real numbers?>On the face of it, it seems like only equality would be a problem, no?>I am talking about a *well*-ordering here, not the usual ordering of the reals.-- Stephen J. Herschkorn herschko@rutcor.rutgers.edu === > Under AC, of course, does there exist an algortihm which develops a>> well-ordering of the reals (not necessarily in finite time) and which>> has the property that, given any two real numbers, it determines in>> finite time which of the two is no greater than the other under this>> ordering?>>Exactly what do you mean by given any two real numbers?>On the face of it, it seems like only equality would be a problem, no???? My best guess here is that you're unaware of what the phrasewell-ordering means, or possibly you missed the fact that we'retalking about _a_ (well-)ordering, not talking about the standardorder on the reals.************************David C. Ullrich === Forget about algorithms. Here is a simpler question:Does there exist an explicit well-ordering of 2^N (the set of all binary sequences)?Again, I suspect not, fora) it probably would be well-known;b) it would yield a well-ordering of R and there wouldn't have been so much controversy about the axiom of choice, andc) it seems to be somehow equivalent to exhibiting an explicit Hamel basis, which I gather is also impossible.-- Stephen J. Herschkorn herschko@rutcor.rutgers.edu === Stephen J. Herschkorn> Forget about algorithms.I will, with pleasure :)> Here is a simpler question:>> Does there exist an explicit well-ordering of 2^N (the set of all> binary sequences)?I expect so, although I haven't seen any. In Conway's theory of surrealnumbers,R gets two different order relations:-- the usual total order; call that T, a subset of RxR.-- a well-founded forest order which we can describe as x is an ancestor ofy;call that relation F.Write W = F cup (F-T). It's not altogether trivial, but W is a well-order.I'll try to come up with something more explicit in terms of binary orternary sequences.Larry === >Forget about algorithms. Here is a simpler question:>>Does there exist an explicit well-ordering of 2^N (the set of all >binary sequences)?No.>Again, I suspect not, for>a) it probably would be well-known;>b) it would yield a well-ordering of R Yes.>and there wouldn't have been so >much controversy about the axiom of choice, and>c) it seems to be somehow equivalent to exhibiting an explicit Hamel >basis, which I gather is also impossible.Hmm, never noticed that. It's clear that a well-ordering of R allowsone to construct a Hamel basis for R over Q; come to think ofit a Hamel basis also allows one to construct a well-ordering.************************David C. Ullrich === > Does there exist an explicit well-ordering of 2^N (the set of all > binary sequences)?There are an explicit bijections between R and 2^N and N^N, sologicians sometimes consider the most convenient one.Goedel defined an explicit well-ordering of a certain subset of R, andshowed that ZF cannot disprove the assertion that the subset is all ofR (provided ZF is consistent).-- G. A. Edgar http://www.math.ohio-state.edu/~edgar/ === I've been seeing this term a lot in James Harris's proofs. Can someoneplease give me the definition, so that I can check those proofs formyself?Jack Rudd === > I've been seeing this term a lot in James Harris's proofs. Can someone> please give me the definition, so that I can check those proofs for> myself?>Algebraic integers are solutions to polynomials x^n + a_(n-1) x^(n-1) +..+ a_1 x + a_0 = 0with integer coefficients and a_n = 1.For example sqr 3, 1 + sqr 2, (1 + sqr 5)/2.Don't feed the troll, maybe it'll go away. === >> I've been seeing this term a lot in James Harris's proofs.> Don't feed the troll, maybe it'll go away.Dear William, I have a bridge to sell. === > I've been seeing this term a lot in James Harris's proofs. Can someone> please give me the definition, so that I can check those proofs for> myself?> Jack RuddFor a complex number to be an algebraic integer, it is necessary and sufficient that it be a zero of an irriducible monic polynomial in one variable with integer coefficients.These form a subset, and subring, of the set, and field, of algebraic numbers, also zeros of polynomials with integer coeficients, but for which the polynomials need not be monic. === In sci.math, Jack Rudd:> I've been seeing this term a lot in James Harris's proofs. Can someone> please give me the definition, so that I can check those proofs for> myself?> Jack RuddFactorization problems are tricky in algebraic integers. Othershave already defined the field, or one can look athttp://planetmath.org/encyclopedia/ AlgebraicInteger.htmlwhich is as good as any although extremely terse (wolfram.comis being fussy today for some reason).However, certain assumptions break down. In particular,1 has an infinite number of factorizations:1 = 1 * 1= (2 - sqrt(3)) * (2 + sqrt(3))= (3 - 2*sqrt(2)) * (3 + 2*sqrt(2))= (4 - sqrt(15)) * (4 + sqrt(15))= (5 - 2*sqrt(6)) * (5 + 2*sqrt(6))= ...= (n - 2*sqrt(n^2-1)) * (n + 2*sqrt(n^2-1))= ...All of these are degree-2 algebraic integers, solutionsof the equation x^2 - 2nx + 1 = 0, for any integer n > 1.(n=1 yields a reducible quadratic; n=0 gives us no realsbut is another factorization: 1 = i * (-i).n = -1 gives us (-1) * (-1); n < -1 gives us the negativesof most of the roots we've found already.)Since Mr. Harris likes to have things dependent on coprimality of 3to a root, it's clear that we have some minor difficulties here.The equation x^2 - (2n+1)x + 1 = 0 yields even more factorizations,which have a 2 in the denominator:1 = ( (-(2n+1) + sqrt(4n^2+4n-3))/2 ) * ( (-(2n+1) - sqrt(4n^2+4n-3))/2 )All these are not integers (except for 1 and -1),but they are algebraic integers.It's also clear that there is no smallest positivealgebraic integer. Consider the equation y^n - 2, n > 1.This equation has n roots, exactly one of which is realand positive (if n is even we get a negative one as well).Subtract 1 from this root (or, if one prefers, solve theequation (x+1)^n-2=0 instead) and one sees that one cangenerate an infinite sequence of algebraic integers inan ordering, each smaller than the last one but all ofthem positive.One can use the above quadratic equation as a generatoras well; the smaller root will tend towards 0 as n getslarger and larger; the bigger root tends towards positiveinfinity.Funny things, these algebraic integers. :-) It's clearMr. Harris is making a strange assumption or two in hisproof.-- #191, ewill3@earthlink.netIt's still legal to go .sigless. === > The square terms in 2^n - 1 make a pretty pattern:> 2^n - 1 divides p if n divides (p - 1)> miniproof:> m = (p - 1) to abbreviate> 2^mn - 1 = (2^m - 1) (2^(n-1)m + 2^(n-2)m + ... + 1)> 2^m = 1 (mod p) of course.> But, apparently, 2^n - 1 divides p^2 iff n divides p(p - 1). Why is that?First, you certainly mean p divides N, i.e. N is a multiple of p,whenever you write N divides p. Secondly, the if part of your apparent iff statement is due to Euler, as phi(p^2)=p(p-1);the only if part is not true, as e.g. 7^2 divides 2^21-1.Miro Chlebik === Fred Galvin escreveu na mensagem> Search the google archives for a posting to this newsgroup by Robin> Chapman with the title Bertrand's Postulate.I did find it, at ===