mm-398 === Subject: : Re: Happy Pi Day charset=iso-8859-7 Richard Henry >> I rarely post on the news group, but I read it alot.> However I just wanted to wish everyone a Happy Pi Day.> March 14th> 3/14gets. The exactly same message has been posted to sci.astro.amateur, whereit has generated a lot of responses as well.Bravo to whoever thought of it.http://users.forthnet.gr/ath/jgal/--Eventually, _everything_ is understandable=== === Subject: : a search for a mathematical expression for mass ratios using a large databaseHello everyboy, I made an experiment over a period of several months using myinverter(the home version with 610 million constants).I took the latest values of the CODATA 2002 NIST table of physicalconstantsand tried a vast experiment to find any reasonable mathematicalexpressionfor those ratios. http://physics.nist.gov/cuu/Constants/Table/allascii.txtI used many simple and naive models to try to find anything, anypossibleexpression as long as it is simple, short and easily explained.Here are the results : http://www.lacim.uqam.ca/~plouffe/Search.htmhttp:// www.lacim.uqam.ca/~plouffe/Search.pdf (is more readable).analysis and an attempt to find a mathematical and simple expressionand NOT any attemptto any physical theory. It is only that couldexistfor those numbers that have been found using what I believe areappropriate tools.The tables I used are the ones on the Inverter and a set ofspecializedtables constructed from the OEIS and my own tables that are not yetpublic.There are 2 main findings : First I discovered a weakness in the PSLQ,LLLor integer relations algorithm that only exist for a specific type ofnumbers.Second, I propose a set of at least 12 values among the 28 knownvalues(actually there are 14 + inverses). In other words, I have amathematicalexpression for 12 of the 14 values. These expressions are allgeneratedby 1 number only.The second finding is related to the first as explained in thePlouffe=== === Subject: : Re: (-2/3)^(-2/3) = (3/2)^(2/3)?> Note that GrafEq plots no points for y = (-2)^(x^x)> where -1 < x < 0.> Is there a mathematical difference between the systems:> |y = (-2)^u |y = (-2)^(x^x)> |u = x^x and |-1 < x < 0> |-1 < x < 0> According to GrafEq the graph of the first system consists of four> curves and infinite vertical line (probably x = 0). The graph of the> second consists of point (probably (-1;-0.5)) and infinite vertical> line (probably x = 0).> So everything is OK?> As far as I can tell, everything is OK with GrafEq. But your statements> about what the graphs consist of according to GrafEq are subtly> incorrect.> I agree with the last sentance. But there are cases in which GrafEq> doesn't plot correctly (it doesn't plot at all) the graph of> mathematical equation or system.Perhaps there are such cases, but I'm not aware of any.> For example from the following system:> |u * u = 2> |x = ((-3)^u)^u> |x belongs to R> => x = -9. Right?If we have the requirement that _all_ results (including intermediate ones)be real, then the graph of the system is clearly empty -- i.e., no pointsshould be plotted -- since (-3)^u is not real. Such a requirement is notunreasonable, esp. for GrafEq, whose interval arithmetic is based onfloating-point arithmetic.However, when asked to graph u * u = 2, x = ((-3)^u)^u, GrafEq shows thetwo vertical lines x = -9 and x = +9, while indicating that its graph isnot yet quite 100% Proven. Due to that indication, I can't see thatGrafEq has done anything wrong in this case.> On that basis the graph of y = ((-2)^sqrt(2))^sqrt(x) should be> visually identical to y = -(2^sqrt(2))^sqrt(x). Right?No. Considering the requirement mentioned in my first sentence above, thegraph of y = ((-2)^sqrt(2))^sqrt(x) should be empty, just as GrafEq showsit to be. In contrast, the graph of y = -(2^sqrt(2))^sqrt(x) is nonempty.For it, GrafEq correctly shows a curve in quadrant IV, starting at (0,-1).David Cantrell=== === Subject: : Mathematical physicsHi all, I am solving a mathematical phsyiscs problem. (about the inducedgravitational potension), I defined 0Suppose the laplace transform of f(x) is f*(s), then, how about the laplace>transform of f(a-x) where a is positive constant?>It seems that there is no definition for the Laplace transform of f(a-x), is>this right?Generally, the function you're taking the Laplace transform of is assumed to be defined on [0,infinity). But as x -> infinity, a-x -> -infinity.So there's no guarantee that f(a-x) is even defined, much less that it has a Laplace transform. But let's suppose f is defined on the wholereal line. Break it into odd and even parts f(x) = f_e(x) + f_o(x)where f_e(-x) = f_e(x) and f_o(-x) = -f_o(x). I'll assume that both f_e and f_o are exponentially bounded, and have Laplace transformsf_e*(s) and f_o*(s) respectively.Then g(x) = f(a-x) = f_e(x-a) - f_o(x-a) has the Laplace transformg*(s) = exp(-sa) (f_e*(s) - f_o*(s) + int_0^a exp(st) f(t) dt)Department of Mathematics http://www.math.ubc.ca/~israel === === Subject: : probability problemSuppose that X,Y are non-negative random variable with the p.d.f. f_X(x) andf_Y(y), respectively. For positve constant a>0,b>0, how to compute thefollowing probability?Pr( X+YX).I got two expressions, I need to know which one is correct.Pr(X+YX) = int_0^b f_X(x) int_0^{a-x}f_Y(y) dydxOrPr(X+YX) = int_0^a f_Y(y) int_0^{min(a-y,b)}f_X(x) dxdy =int_0^{a-b}f_Y(y) int_0^b f_X(x)dxdy +int_{a-b}^a f_Y(y) int_0^{a-y}f_X(x) dxdyThank you very much for your suggestions.ZHANG Yanhttp://www.ntu.edu.sg/home5/pg01308021=== === Subject: : Re: probability problem>Suppose that X,Y are non-negative random variable with the p.d.f. f_X(x) and>f_Y(y), respectively. For positve constant a>0,b>0, how to compute the>following probability?>Pr( X+YX).I hope you're assuming X and Y are independent, otherwise there's no wayto compute the answer using f_X and f_Y. The answer will be the double integral of f_X(x) f_Y(y) over the region x+y 0.>I got two expressions, I need to know which one is correct.>Pr(X+YX) = int_0^b f_X(x) int_0^{a-x}f_Y(y) dydxOK if a >= b. In general the x integral should be from 0 to min(a,b).>Or>Pr(X+YX) = int_0^a f_Y(y) int_0^{min(a-y,b)}f_X(x) dxdyOK> =int_0^{a-b}f_Y(y) int_0^b f_X(x)dxdy +>int_{a-b}^a f_Y(y) int_0^{a-y}f_X(x) dxdyAgain, OK if a>=b.Department of Mathematics http://www.math.ubc.ca/~israel === === Subject: : Re: probability problemThank you very much for the comments.ZHANG Yanhttp://www.ntu.edu.sg/home5/pg01308021>Suppose that X,Y are non-negative random variable with the p.d.f. f_X(x)and>f_Y(y), respectively. For positve constant a>0,b>0, how to compute the>following probability?>Pr( X+YX).> I hope you're assuming X and Y are independent, otherwise there's no way> to compute the answer using f_X and f_Y. The answer will be the double> integral of f_X(x) f_Y(y) over the region x+y 0.>I got two expressions, I need to know which one is correct.>Pr(X+YX) = int_0^b f_X(x) int_0^{a-x}f_Y(y) dydx> OK if a >= b. In general the x integral should be from 0 to> min(a,b).>Or>Pr(X+YX) = int_0^a f_Y(y) int_0^{min(a-y,b)}f_X(x) dxdy> OK> =int_0^{a-b}f_Y(y) int_0^b f_X(x)dxdy +>int_{a-b}^a f_Y(y) int_0^{a-y}f_X(x) dxdy> Again, OK if a>=b.> Department of Mathematics http://www.math.ubc.ca/~israel> University of British Columbia> Vancouver, BC, Canada V6T 1Z2=== === Subject: : Re: Copyrights, fair use, and Internet realities>>That's the issue, using another person's work for your own personal>>gain, and here it's about drawing attention.>>I noticed Winter's pages by doing a Google search on *my* name and>>math.>>Searching google for yourself? That's slightly pathetic.>Just for fun I did a Google search on my name just now. You>think you got troubles, there are plenty of other people out there>using my name! (Also various usenet posts from me show up>on various sites. Doesn't bother me a bit - if I didn't want to>make whatever I'd said public why would I have posted it?)> g! All I got was newsgroup posts and a few friends linking to my > site. Oh yeah, and my site as well. I guess I need to get more> famous. Try having the same name as a famous sports star who has hundreds oftribute websites exist. It has taken me 4 years to get my name beforehis in Google. === === Subject: : Re: Copyrights, fair use, and Internet realities>That's the issue, using another person's work for your own personal>gain, and here it's about drawing attention.>I noticed Winter's pages by doing a Google search on *my* name and>math.>Searching google for yourself? That's slightly pathetic.>>Just for fun I did a Google search on my name just now. You>>think you got troubles, there are plenty of other people out there>>using my name! (Also various usenet posts from me show up>>on various sites. Doesn't bother me a bit - if I didn't want to>>make whatever I'd said public why would I have posted it?)>g! All I got was newsgroup posts and a few friends linking to my >site. Oh yeah, and my site as well. I guess I need to get more>famous. > Try having the same name as a famous sports star who has hundreds of> tribute websites exist. It has taken me 4 years to get my name before> his in Google. > Well, if you just google on Twentyman, you get a ton of hits for some psychologist as a citation. I haven't done that search in a while, though.Will Twentymanemail: wtwentyman at copper dot net=== === Subject: : Re: Copyrights, fair use, and Internet realitiesContent-transfer-encoding: 8bit>That's the issue, using another person's work for your own personal>gain, and here it's about drawing attention.>I noticed Winter's pages by doing a Google search on *my* name and>math.>> Searching google for yourself? That's slightly pathetic.> Just for fun I did a Google search on my name just now. You>> think you got troubles, there are plenty of other people out there>> using my name! (Also various usenet posts from me show up>> on various sites. Doesn't bother me a bit - if I didn't want to>> make whatever I'd said public why would I have posted it?)> g! All I got was newsgroup posts and a few friends linking to my > site. Oh yeah, and my site as well. I guess I need to get more> famous. > Try having the same name as a famous sports star who has hundreds of> tribute websites exist. It has taken me 4 years to get my name before> his in Google. Uh, let me guess. You're there now because he died?--Ron Bruck=== === Subject: : New Binary Numbers -- Where to Publish? I have named two new Binary numbers and am wondering where I mightpublish them. Any ideas? The abstract for the paper follows:AbstractThis brief paper discusses the naming of two Binary Numbers. Theirnames are: the goobi, which is 2^(10*33.3) and the goxbi, which is2^goobi. Relevant background material has been included as well as athorough derivation and error analysis. These numbers have not beendescribed elsewhere and, as such, are a unique contribution to thefield of Binary Number Theory. The actual application of these numbersis difficult to imagine; however, fractional components may find theirway into algorithms such as encryption, etc.Cheers!Bruce=== === Subject: : Re: New Binary Numbers -- Where to Publish?> I have named two new Binary numbers and am wondering where I might>publish them. Any ideas?Seems exactly right for a paper in the Annals.> The abstract for the paper follows:>Abstract>This brief paper discusses the naming of two Binary Numbers. Their>names are: the goobi, which is 2^(10*33.3) and the goxbi, which is>2^goobi. Relevant background material has been included as well as a>thorough derivation and error analysis. These numbers have not been>described elsewhere and, as such, are a unique contribution to the>field of Binary Number Theory. The actual application of these numbers>is difficult to imagine; however, fractional components may find their>way into algorithms such as encryption, etc.>Cheers!>Bruce=== === Subject: : Re: New Binary Numbers -- Where to Publish?===> === Subject: : New Binary Numbers -- Where to Publish?>Message-id: <3661e372.0403152023.7390aa1e@posting.google.com> I have named two new Binary numbers and am wondering where I might>publish them. Any ideas? The abstract for the paper follows:>Abstract>This brief paper discusses the naming of two Binary Numbers. Their>names are: the goobi, which is 2^(10*33.3) Why don't you just say 2^333?>and the goxbi, which is>2^goobi. Relevant background material has been included as well as a>thorough derivation and error analysis. These numbers have not been>described elsewhere and, as such, are a unique contribution to the>field of Binary Number Theory. The actual application of these numbers>is difficult to imagine; however, fractional components may find their>way into algorithms such as encryption, etc.>Cheers!>Bruce=== === Subject: : Re: Point on the sphere equidistant from two others > [ ... ] Since your sphere has no> boundary in 3-space, any maximum or minimum will be inside the sphere> (am I right on this?) Um, that sounds right. I was looking for a solution *on* the sphere, btw, I think what you call S2. Anyway, thanks to all!=== === Subject: : Re: Beware undergrads, copiers of your posts> Just so you know, there are people who might copy your posts and put> them up on a webpage!Free publicity!=== === Subject: : Algebra QuestionIf f:G->H is a group epimorphism,Is it impossible |G|>|H|?I read following :If f:G->H is a group epimorphism and K is a subgroup of HThen, f^-1(K) is a subgroup of G.But, before saying that,I think we must convince that f^-1 is well-defined And I'm not sure that.How can I show f^-1:K->G is a well-defined function?If somebody can help me, please post reply.=== === Subject: : Re: Algebra Question Adjunct Assistant Professor at the University of Montana.>If f:G->H is a group epimorphism,>Is it impossible |G|>|H|?In fact, if G maps epimorphically (in the category of all groups, Iassume) onto H, then the map is surjective, so |G| is at least as bigas |H|, and can certainly be larger; for example, Z/4Z = G maps ontoZ/2Z = H, and |G|=4 > 2 = |H|>I read following :>If f:G->H is a group epimorphism and K is a subgroup of H>Then, f^-1(K) is a subgroup of G.>But, before saying that,>I think we must convince that f^-1 is well-defined >And I'm not sure that.Given any map f:A->B from a set A to a set B, there are two inducedfunctions, g:P(A) -> P(B), and h:P(B)->P(A), where P(A) is the powerset of A (the set of all subsets of A) and P(B) is the power set of B.The function g maps a subset X of A to g(X) = { f(x): x in X}, whichis a subset of B.The function h maps a subset Y of B to h(Y) = {x in A: f(x) is in Y}.g is called the direct image map, and h is called the inverse imagemap. By abuse of notation, g is often denoted by f and h by f^{-1}Here, f^{-1}(K) = { g in G: f(k) is in K}.=========== === Subject: : Re: Algebra Question> If f:G->H is a group epimorphism,> Is it impossible |G|>|H|?Yes. Let G be a finite group. Now consider the projection GxG --> G.> But, before saying that,> I think we must convince that f^-1 is well-defined > And I'm not sure that.It is bad notation, but it is nevertheless standard notation. If f isbijective, f^-1 denotes the (well-defined) inverse function. In generalone uses denotes by f^-1(K) the set of points in G mapped into K by f.Note that these two notations are (almost) consistent. Michael Knudsen=== === Subject: : Re: Algebra QuestionMichael Knudsen a .8ecrit:>If f:G->H is a group epimorphism,>Is it impossible |G|>|H|?> Yes. Let G be a finite group. Now consider the projection GxG --> G.>But, before saying that,>I think we must convince that f^-1 is well-defined >And I'm not sure that.> It is bad notation, but it is nevertheless standard notation. If f is> bijective, f^-1 denotes the (well-defined) inverse function. I'm trying to promotethe notationf for direct imageand f^-1 for inverse image( instead of f(A) and f^-1(A) )In that case f(x) is used only for elements, not for sets.Seems all benefice and no price to pay.Of course, later, when f(x) is written fx to gain place...>In general> one uses denotes by f^-1(K) the set of points in G mapped into K by f.> Note that these two notations are (almost) consistent. === === Subject: : Re: Algebra Question Adjunct Assistant Professor at the University of Montana.>I'm trying to promotethe notation>f for direct image>and f^-1 for inverse image>( instead of f(A) and f^-1(A) )>In that case f(x) is used only for elements, not for sets.What is an element? In the usual set theory, elements are alwayssets. So which one do we use?If you really want to avoid abuse, then you need different symbols forthe direct and inverse image functions. I seem to remember a bookthat, for a whole chapter, given f:A->B used an underlined f for theassociated direct image function P(A)->P(B), and an overlined f forthe associated inverse image function P(B)->P(A). >Seems all benefice and no price to pay.There is little no cost in the usual abuse of notation: that is why itis permitted. Context will almost invariably tell you whether you aretalking about the function, the direct image function, or the inverseimage function. It is usually a very technical or contrived situationin which this is not the case (e.g., when the domain is an ordinal, sothat certain elements are also subsets), in which case any distinctionwill work.=========== === Subject: : Re: Algebra Question> I read following :> If f:G->H is a group epimorphism and K is a subgroup of H> Then, f^-1(K) is a subgroup of G.> But, before saying that,> I think we must convince that f^-1 is well-defined > And I'm not sure that.> How can I show f^-1:K->G is a well-defined function?It's not a function, but it's well-defined. In this context, f^-1(K) just means {g in G : f(g) is in K}.=== === Subject: : Re: locally compact space with an intrinsic metric> An intrinsic metric is defined to be one such that for any two points> x and y, there is a third point z such that d(x,z)=d(y,z)=1/2 d(x,y).> In the book I'm reading it says that in a locally compact space with> an intrinsic metric, every bounded and closed set is compact. Does> anyone know how to prove that?> (0,1) with the usual metric would appear to be a counterexample.Really? Surely Heine-Borel applies to (0,1).What am I missing?=== === Subject: : Re: locally compact space with an intrinsic metric=== === Subject: : Re: locally compact space with an intrinsic metric > An intrinsic metric is defined to be one such that for any two > two points x and y, there is a third point z such that > d(x,z)=d(y,z) = 1/2 d(x,y). > In the book I'm reading it says that in a locally compact space > with an intrinsic metric, every bounded and closed set is compact. > Does anyone know how to prove that? >> (0,1) with the usual metric would appear to be a counterexample. >Really? Surely Heine-Borel applies to (0,1). >What am I missing?I = (0,1) is locally compact and the usual metric is intrinsic.Now bounded (0,1/2] is closed subset of I, but it's not compact.----=== === Subject: : Re: locally compact space with an intrinsic metric...> I = (0,1) is locally compact and the usual metric is intrinsic.> Now bounded (0,1/2] is closed subset of I, but it's not compact.Oops, yeah. Guess I shoulda just remembered that (0,1) ishomeomorphic to R. And that boundedness is not a topologicalproperty.=== === Subject: : Re: locally compact space with an intrinsic metric>An intrinsic metric is defined to be one such that for any two points>x and y, there is a third point z such that d(x,z)=d(y,z)=1/2 d(x,y).>In the book I'm reading it says that in a locally compact space with>an intrinsic metric, every bounded and closed set is compact. Does>anyone know how to prove that?>(0,1) with the usual metric would appear to be a counterexample.> Really? Surely Heine-Borel applies to (0,1).Uh? The space (0,1) is a bounded and closed subset of itself, but it isnot compact. Notice that it's (0,1) (or ]0,1[ if you prefer, as I do)that we are talking about here, not [0,1].Jose Carlos Santos=== === Subject: : Re: locally compact space with an intrinsic metric> Really? Surely Heine-Borel applies to (0,1).> Uh? The space (0,1) is a bounded and closed subset of itself, but it is> not compact. Notice that it's (0,1) (or ]0,1[ if you prefer, as I do)> that we are talking about here, not [0,1].Right, thanks. It was an amusing glitch -- yes I know (0,1)is not compact, but for some reason I thought it *could* becompact when viewed as a space in its own right, since thatmakes it a closed set and I remembered (or rather knee-jerked)Heine-Borel. But of course that's silly, it's not closed inR. Now excuse me, I think I will slink away quietly with myMunkres and do as many problems as it takes to fix my b0rkenintuition.=== === Subject: : Re: Find the third point of a triangle> I have a Traingle ABC. I have the position of two of the points say A> (x1,y1) and B (x2,y2). I also have the length of line segments AB and> BC.> Q) How do I find the position of the third point on a 2D plane, in> this case C ?There are an infinite number of solutions to this problem. Any pointon the circle with radius BC center B will work, other than the twopoints on the circle where C would be in a straight line with A and B.Of course, if you know the coordinates of A and B, you already knowthe distance between A and B, so I think you meant to say that youknow the lengths of AC and BC. If so, use the type of solution theguy above posted.=== === Subject: : Re: Find the third point of a triangle> * m@hotmail.com> I have a Traingle ABC. I have the position of two of the points say A> (x1,y1) and B (x2,y2). I also have the length of line segments AB and> BC.> Q) How do I find the position of the third point on a 2D plane, in> this case C ?> Is this homework? If so, please tell us so. If not, I apoligize, but> still, please tell us that too.> Anyway, consider an easier case, where (x1,y1)=(0,0) and> (x2,y2)=(1,0), and AB and BC is u and v respectively. I am sure you> can, by using Pythagoras, come up with two equations involving the> third point (x3,y3) and the lengths u and v.> Two equations with two unknowns are solvable.> After that, generalize.No this not HW, this is for an image processing application.I alsoforgot to add, I have the angle B of the triangle ABC.=== === Subject: : Re: Find the third point of a triangle wibbled:> forgot to add, I have the angle B of the triangle ABC.I was gonna say, there was insufficent information before.You can derive the equation for the edge BC from the one for AB plus the angle. Then you can find the point on that that's the right distance from A. In some cases there may be two, but you probably don't want scalene triangles so you take the one that makes BC shortest.=== === Subject: : Re: Find the third point of a triangle> I have a Traingle ABC. I have the position of two of the points say A> (x1,y1) and B (x2,y2). I also have the length of line segments AB and> BC.> Q) How do I find the position of the third point on a 2D plane, in> this case C ?> How many answers would you like?Just one answer would be nice, since I am implementing this in C++,want to keep it simple....not sure if it is a simple problem though.I also forgot to add, I have the angle B of the triangle ABC=== === Subject: : Re: Find the third point of a triangle> I have a Traingle ABC. I have the position of two of the points say A> (x1,y1) and B (x2,y2). I also have the length of line segments AB and> BC. How do I find the position of the third point on a 2D plane, in> this case C ? .. I have the angle B of the triangle ABCReduce length AB at tip B by BC cos B and go up a perpendicular distance of BC sin B to reach C.=== === Subject: : Re: Find the third point of a triangle> I have a Traingle ABC. I have the position of two of the points say A> (x1,y1) and B (x2,y2). I also have the length of line segments AB and> BC.> Q) How do I find the position of the third point on a 2D plane, in> this case C ?> How many answers would you like?> Just one answer would be nice, since I am implementing this in C++,> want to keep it simple....not sure if it is a simple problem though.> I also forgot to add, I have the angle B of the triangle ABCThat significantly reduces the number of correct answers.=== === Subject: : Re: Find the third point of a triangle> I have a Traingle ABC. I have the position of two of the points say A> (x1,y1) and B (x2,y2). I also have the length of line segments AB and> BC.> Q) How do I find the position of the third point on a 2D plane, in> this case C ?I also forgot to add, I have the angle B of the triangle ABC=== === Subject: : Re: Find the third point of a triangle>I have a Traingle ABC. I have the position of two of the points say A>(x1,y1) and B (x2,y2). I also have the length of line segments AB and>BC. >Q) How do I find the position of the third point on a 2D plane, in>this case C ? >I also forgot to add, I have the angle B of the triangle ABCWell, then it's easy. I assume the angle B goes clockwise fromBA to BC. If u=(u1,u2) is the unit vector (x1-x2, y1-y2)/sqrt((x1-x2)^2+(y1-y2)^2) in the direction of the vector BA, then the unit vector in the direction of BC isv = (cos(B) u1 - sin(B) u2, cos(B) u2 + sin(B) u1),and C = B + |BC| v.Department of Mathematics http://www.math.ubc.ca/~israel === === Subject: : Re: Ln typo or....?|This problem is so fundamental that solving it with techniques of |integration learned in calculus class runs the risk of making it|seem harder than it is, and obscuring the geometry involved.||How about this:||Take the region under the curve y = 1/x from x = 1 to x = a.|If you stretch this region horizontally by the factor b and |squash it vertically by the same factor, you get another region |of the same area. And, this is the region under the curve |y = 1/x from x = b to x = ab. It follows that||ln(ab) - ln(b) = ln(a) - ln(1)||and since ln(1) = 0, we get||ln(ab) = ln(a) + ln(b).You are so clever that you don't even realize that it takesmore cleverness to find this trick geometrically than it doesusing techniques of integration! Asking people to convert thisintegral to that one using a technique of integration is onething; asking them to show that two areas are the same,why that's completely different. :-)If we're trying to be cute....Another way to look at this is that dx/x is an invariantmeasure under multiplication. If we substitute x=cu,dx/x becomes du/u. Multiplication is a group operation.The function log(x) defined as the integral from theidentity element 1 to x of this invariant measure is thena homomorphism from this group (on the positive reals)to the additive group of the reals.Keith Ramsay=== === Subject: : radius of a bounding circleWhat is the most efficient way to find the radius of the bounding circle ofa shape with 3 corners (like triangle) or shape with 4 corners or shape withfive corners.I think that we should find the center of the mass and check the largestdistance.But Im not sure if this is the best (optimal) way to do this..=== === Subject: : Re: radius of a bounding circle 3QLpj-NoP*NzsIC,boYU]bQ]H'y<#4ga3$21:> way to find the radius of the bounding circle of a shape with 3 > corners (like triangle) or shape with 4 corners or shape with five > corners.This may be more general than you need, but:http://www.inf.ethz.ch/personal/gaertner/ miniball.htmlDavid Eppstein http://www.ics.uci.edu/~eppstein/Univ. of California, Irvine, School of Information & Computer Science=== === Subject: : Re: Abstract Algebra Question, Please Help!>I received an email from Dik Winter proclaiming that he would *not*>remove my writing from his webpage, and he claims he is not violating>international copyright laws.Dear Mr. Harris,I've been happily filtering your threads out for years now, thusavoiding the usual harassment going on with them: I'm *not* interestedin commenting or discussing either their mathematical content and thetypical issues involved therein or the specific, OT issue that youbrought to the attention here, but I feel like acknowledging thatAFAIK you've been behaving correctly as far as avoiding intrusions inothers' threads is concerned, hence the painless filtering hintedto above. SO I'M ASKING YOU TO BE SO KIND AND CONTINUE WITH THISSUCCESSFUL POLICY: please go and discuss your flt/personal issueselsewhere!Micheleyou'll see that it shouldn't be so. AND, the writting as usuall isfantastic incompetent. To illustrate, i quote:- Xah Lee trolling on clpmisc, perl bug File::Basename and Perl's nature=== === Subject: : Is there an adaptation of Pollard Rho for factoring 2^p+1Hans Riesel in his book on primes and factoring describes how thefactors of a^p +/- b^p, for odd prime p all have the form 2kp+1.He goes on to describe how some factoring methods can take advantageof this special case. For example, trial division can just try thesepossible factors, using Euclid's algorithm for the gcd of a productand the number can be adapted, Fermat's method can be adapted.What he does not mention is whether there might be an adaptation ofthe Pollard Rho method, or something similar.Is there a way to modify the Pollard Rho method so that it generatesan excess of terms of the form 2kp+1? Or other algorithms that mightapply in this special case?I've done some searching and not found anything thus far.Thank you(email address is valid, if it matters)=== === Subject: : Re: Is there an adaptation of Pollard Rho for factoring 2^p+1>Hans Riesel in his book on primes and factoring describes how the>factors of a^p +/- b^p, for odd prime p all have the form 2kp+1.>He goes on to describe how some factoring methods can take advantage>of this special case. For example, trial division can just try these>possible factors, using Euclid's algorithm for the gcd of a product>and the number can be adapted, Fermat's method can be adapted.>What he does not mention is whether there might be an adaptation of>the Pollard Rho method, or something similar.>Is there a way to modify the Pollard Rho method so that it generates>an excess of terms of the form 2kp+1? Or other algorithms that might>apply in this special case?>I've done some searching and not found anything thus far.>Thank you>(email address is valid, if it matters) Instead of using f(x) = x^2 +- 1 in Pollard Rho, make theexponent a multiple of 2p, such as f(x) = x^(24*p) + 1. Each prime factor q of 2^p - 1, p odd, is +- 1 (mod 8), since 2is a quadratic residue. Hence gcd(q-1, 24*p) is 2p, 6p, 8p, or 24p.If, say, this GCD is 6*p, then all iterations after the firstwill map into a subset of Z/qZ of order (q - 1)/(6*p) + 1rather than (q - 1)/2 + 1. Since its size has been reduced by a factorapproximately 3*p, the number of iterations needed to find q will dropby a factor approximately sqrt(3*p). The cost of an iterationwill be about log(24*p)/log(2) times as much. If, say, p is near 10000, the cost of an iteration will be about23 multiplications with exponent near 240000, but the number of iterationsdrops by a factor of 170, so you get a 7-fold speed-up. Richard Brent and John Pollard used this method to factor 2^256 + 1.John Adams served two terms as Vice President and one as President, but lostreelection. Later his son became President despite losing the popular vote.That son lost his reelection attempt badly. Now history is repeating itself.pmontgom@cwi.nl Microsoft Research and CWI Home: San Rafael, California=== === Subject: : Math required to understand the proof of the Banach-Tarski theoremHi all,I'd like to know if anyone could recommend a text (or sequence oftexts) that would give me sufficient background to tackle the proof ofthe B-T theorem.I've looked on Amazon an found: The Banach-Tarski Paradox(Encyclopedia of Mathematics & Its Applications S.) - Steve Wagon,ISBN: 0521457041.Has anyone had experience with this book? Is it an introductory text?Can anyone suggest a better book?Simon.=== === Subject: : Re: Math required to understand the proof of the Banach-Tarski theorem> Hi all,> I'd like to know if anyone could recommend a text (or sequence of> texts) that would give me sufficient background to tackle the proof of> the B-T theorem.> I've looked on Amazon an found: The Banach-Tarski Paradox> (Encyclopedia of Mathematics & Its Applications S.) - Steve Wagon,> ISBN: 0521457041.> Has anyone had experience with this book? Is it an introductory text?> Can anyone suggest a better book?Killer book. Highly recommended.=== === Subject: : re:Math required to understand the proof of the Banach-Tarski tYou don't really need much background to do that.The required material for understanding the proof is Zorn's lemma,Cantor-Berstein theorem and free groups.It is covered in most introductory texts to set theory and grouptheory.Once you learn those topics come back and I'll give you some hints forproving the theorem. === === Subject: : Re: re:Math required to understand the proof of the Banach-Tarski tX-RFC2646: OriginalCool..Any suggestions on a good introductory text?Simon.> You don't really need much background to do that.> The required material for understanding the proof is Zorn's lemma,> Cantor-Berstein theorem and free groups.> It is covered in most introductory texts to set theory and group> theory.> Once you learn those topics come back and I'll give you some hints for> proving the theorem.------------------------------------------------------- ---> ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **> ----------------------------------------------------------> === === Subject: : Re: Math required to understand the proof of the Banach-Tarski theorem> Hi all,> I'd like to know if anyone could recommend a text (or sequence of> texts) that would give me sufficient background to tackle the proof of> the B-T theorem.> I've looked on Amazon an found: The Banach-Tarski Paradox> (Encyclopedia of Mathematics & Its Applications S.) - Steve Wagon,> ISBN: 0521457041.> Has anyone had experience with this book? Is it an introductory text?> Can anyone suggest a better book?It's a book that requires some mathematical maturity but I foundit an excellent read. (CUP did publish a paperback version---dunno if it's still in print).Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: Packing squares into a 1 x Zeta[2] rectangle>> But as a matter of interest,>> how did you deal with pi^2 using exact arithmetic?> Mathematica does it all for me. Mathematica can do comparisons between,> for example, rational numbers and transcendentals. Here is a short> Mathematica session in which it compares a rational, num/denom, withpi+e> and prints the result Greater, it then compares the rational> (num-1)/denom with pi+e and prints the result Not greater:> In[1]:= $MaxExtraPrecision = 100> Out[1]= 100> In[2]:= num = 6083355812763767537862691282377375125710417240146> Out[2]= 6083355812763767537862691282377375125710417240146> In[3]:= denom = 1038137562741240040724843633763265660486107102341> Out[3]= 1038137562741240040724843633763265660486107102341> In[4]:= If[num/denom > Pi + E, Print[Greater], Print[Not greater]]> In[5]:= If[(num - 1)/denom > Pi + E, Print[Greater], Print[Not> greater]]> I'm not entirely clear what this is doing.> using exact arithmetic (the BigInteger class).> It was actually impossible to get much past 10000> as the numerators and denominators get too big.> So I wonder if Mathematica actually works with floating-point numbers> to a certain (high) precision?It will hold a rational quantity as an exact fraction (reduced to its lowestterms). It will hold a value such as 840/1010+pi as the rational number84/101 plus the known constant pi. If it needs to compare that value with,say, 10429/8310+e it will subtract one from the other to give-355289/839310-e+pi and then compute that quantity with sufficientprecision to determine if it is positive or negative.> One interesting point is that several other rectangles I tried> with the same area pi^2/6 could not be packed with these squares,> eg pi/2 x pi/3 and pi/sqrt(6) x pi/sqrt(6).> In fact 1 x pi^2/6 is the only packable rectangle of this area> that I have found, though I didn't made a serious study.> Incidentally I took pi=355/113, which I think is just good enough> for the range I was considering.It is difficult to say what approximation to pi is good enough for packing agiven set of squares. Since 355/133 is a little greater than pi it ispossible that a square might just get squeezed in somewhere when it reallyshould not have fitted.Taking one more term in the continued fraction for pi gives the rationalapproximation 103993/33102 which is about 6*10^-10 less than pi. Using myMathematica program I can pack 100,000 squares into a 1 by(103993/33102)^2/6 rectangle in about 3 minutes. [As opposed to about 12minutes when using the exact value for pi.]> I always took the square 1/n x 1/n from the smallest vacant rectangle.> I don't know if another choice would be as good, or even better.> The average rectangle had been divided about 50--100 times> with 10000 squares, which I found surprising> as the number of remaining rectangles was (of course) a little under10000.=== === Subject: : Re: Packing squares into a 1 x Zeta[2] rectangle> Using my> Mathematica program I can pack 100,000 squares into a 1 by> (103993/33102)^2/6 rectangle in about 3 minutes. [As opposed to about 12> minutes when using the exact value for pi.]... and I can pack 1,000,000 squares into a 1 by (103993/33102)^2/6rectangle in about 3.5 hours. [As opposed to about 11 hours when using theexact value for pi.]=== === Subject: : Re: Can someone help me with an algebra problem?> Hi all, this one's got me stuck, and I'm not sure if it's because it's> particularly hard, or because I'm just braindead this week. Can> someone just give me a hint?> Problem:> Let R integral over R. If R is local, prove that S has only finitely many> maximal ideals.> The first thing I notice is that all maximal ideals of S must lie over> the maximal ideal of R (Lang's Algebra, Prop VII.1.11), but I can't> get anywhere past that. The only ascending chain I can think of would> be to take the infinite intersection of all max ideals of S, then all> except one, all except two, etc., but that seems totally useless and> doesn't use the maximal ideal of R anyway.Let m be the maximal ideal of R and M = mS. Now M =/= S dueto the integrality of the extension.By the theory of primary decompostion, the set of prime idealsof S containing M has a finite number of minimal elementsP_1, ..., P_k. I claim that these are all the maximal ideals of S.If Q is a maximal ideal of S then Q contains some P_j, but alsoQ intersect R = P_j intersect R = m. Thus by the lying-over theorem(using S is integral over R) Q = P_j.Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: Can someone help me with an algebra problem?> Let m be the maximal ideal of R and M = mS. Now M =/= S due> to the integrality of the extension.> By the theory of primary decompostion, the set of prime ideals> of S containing M has a finite number of minimal elements> P_1, ..., P_k. I claim that these are all the maximal ideals of S.> If Q is a maximal ideal of S then Q contains some P_j, but also> Q intersect R = P_j intersect R = m. Thus by the lying-over theorem> (using S is integral over R) Q = P_j.TYVM for your answer. At first look, I don't know how (or if) you canget that from Lang's book, which is the only book I have access to,but I'll keep trying.-Rob=== === Subject: : Re: Cantor's Diagonal ArgumentIn sci.logic, |-|erc:>> I have :> for all n, for all i, exists j>> b(n)_i = c(j)_i>& b(n)_1 = c(j)_1>& b(n)_2 = c(j)_2>up to _i> You want :> for all n, exists j, for all i>> b(n)_i = c(j)_i> where>> b = DIAG>> c = COMPUTABLES>That's right, and they're different.>agreed, but is it significant?>they both mean the number is on the list to any degree required.>the 1st digit is on the list,>and the 2nd digit is on the list too,>and the 3rd digit is on the list too>....>all digits are on the list>therefore the number is on the list.> I'll introduce a function> Equals(DE1, DE2, n) {> if (n = 0) {> Return TRUE> }> elseif (DE1_n = DE2_n) {> Equals(DE1, DE2, n-1)> }> else {> Return FALSE> }> }> Forall n, Equals(DE1, DE2, n) -> DE1 = DE2> If extended to handle recurring 9s,> does this satisfy the accepted definition of = ?It might, but I fail to see how it solves the problem.> Herc#191, ewill3@earthlink.netIt's still legal to go .sigless.=== === Subject: : Re: Cantor's Diagonal ArgumentIn sci.logic, |-|erc:>I have :>for all n, for all i, exists j> b(n)_i = c(j)_i> & b(n)_1 = c(j)_1> & b(n)_2 = c(j)_2> up to _iNo, for *all* i, not just i <= n.>You want :>for all n, exists j, for all i> b(n)_i = c(j)_i>where>b = DIAG>c = COMPUTABLES>That's right, and they're different.> agreed, but is it significant?Quite significant.Suppose, just for whimsy's sake, I generate a series of binarynumbers d(j). These numbers are as follows:j <-> d(j)0 <-> 0.000000...1 <-> 0.100000...2 <-> 0.010000...3 <-> 0.110000...4 <-> 0.001000...5 <-> 0.101000...6 <-> 0.011000...7 <-> 0.111000...8 <-> 0.000100...As you can see, I'm writing the number backwards on the right.I can formalize this with a little work but the idea should beclear enough.Now take b = 1/3, and express it in binary:b = .010101010101...It's clear that for all i, there exists a j such thatc(j)_i = b_i(one can take j = 0 if i is odd, and j = 2^(i-1) if i is even)but there is no j such that, for all i,c(j)_i = b_ias that would require 1/3 = 2^(-k) * m for some k and m, whichis not possible.> they both mean the number is on the list to any degree required.> the 1st digit is on the list,> and the 2nd digit is on the list too,> and the 3rd digit is on the list too> ....> all digits are on the list> therefore the number is on the list.>The computable numbers are countable. The real numbers are not.> fantacy, non computable number is a misnomer.I can show non-computable numbers without difficulty,by noting that a UTM must accept at most a finite machinespecifier which is therefore mappable to an integer.Since the reals are not mappable to the set of integers(pick one of Cantor's proofs), uncomputable numbers exist.A nasty situation but what can I do? :-)> Herc#191, ewill3@earthlink.netIt's still legal to go .sigless.=== === Subject: : Re: Cantor's Diagonal Argument oo ____|mn / /_/ / _ / K-9/ /_/ - www.YeOldeCoffeeShoppe.com -/____/_____-------------->> I have :> for all n, for all i, exists j>> b(n)_i = c(j)_i> & b(n)_1 = c(j)_1> & b(n)_2 = c(j)_2> up to _i> No, for *all* i, not just i <= n.non comprendez, n is irrelevant its just the particular b.if you said i You want :> for all n, exists j, for all i>> b(n)_i = c(j)_i> where>> b = DIAG>> c = COMPUTABLES> That's right, and they're different.>> agreed, but is it significant?> Quite significant.> Suppose, just for whimsy's sake, I generate a series of binary> numbers d(j). These numbers are as follows:> j <-> d(j)> 0 <-> 0.000000...> 1 <-> 0.100000...> 2 <-> 0.010000...> 3 <-> 0.110000...> 4 <-> 0.001000...> 5 <-> 0.101000...> 6 <-> 0.011000...> 7 <-> 0.111000...> 8 <-> 0.000100...> As you can see, I'm writing the number backwards on the right.> I can formalize this with a little work but the idea should be> clear enough.> Now take b = 1/3, and express it in binary:> b = .010101010101...> It's clear that for all i, there exists a j such that> c(j)_i = b_i> (one can take j = 0 if i is odd, and j = 2^(i-1) if i is even)> but there is no j such that, for all i,> c(j)_i = b_i> as that would require 1/3 = 2^(-k) * m for some k and m, which> is not possible.granted, but examine this list> 0 <-> 0.000000...> 1 <-> 0.1...> 2 <-> 0.01...> 3 <-> 0.11...> 4 <-> 0.001...> 5 <-> 0.101...> 6 <-> 0.011...> 7 <-> 0.111...> 8 <-> 0.0001...where the initial sequence is repeating, the second number is 0.010101010..> they both mean the number is on the list to any degree required.> the 1st digit is on the list,> and the 2nd digit is on the list too,> and the 3rd digit is on the list too> ....> all digits are on the list> therefore the number is on the list.>> The computable numbers are countable. The real numbers are not.> fantacy, non computable number is a misnomer.> I can show non-computable numbers without difficulty,> by noting that a UTM must accept at most a finite machine> specifier which is therefore mappable to an integer.> Since the reals are not mappable to the set of integers> (pick one of Cantor's proofs), uncomputable numbers exist.> A nasty situation but what can I do? :-)You do OK, but that is purely arguing backwards from the task at hand.What I need is a pure functional program to demonstrate my point. Ituses the First function that takes input from a stream even if infinite.first(3, <5,4,3,2,2>) = <5,4,3first(2, N) = <1,2This is normally used on the keyboard as input to allow for interaction evenwith pure functional constructs.It relies on the language parser being lazy. Lazy means it wont try to storeN in memory, complete that task(!), then copy the 1st 2 numbers. All the parametersare utilised as needed.Would a pure functional program find a 1 to 1 correspondence between N and R?I'm sure it would. Given the input stream b_n, as the digits are processed it wouldjust calculate what computable number it maps to. As more digits are processedthe number is found further down the list. At any point in time the progress can be testedand any number input will be found.1/3 forms a pattern in binary, we can systematically determine its not on that binary list.But how can you determine a number is not on the list of computables? Every digitsequence is covered WITHOUT inherent patterns partitioning classes.Also, different UTMs provide different orderings to the same list of computable numbers.How can you determine that a number fails on all of them?Herc=== === Subject: : Re: Rolling a Dice for 1000 times.In sci.math, Phil Carmody:>The probability of rolling a die and having it come up 6>100 times in a row is 1/6^100, or about 1.53 * 10^-78.>That's about the reciprocal of the number of atoms in the>Universe; if each of them were a die, and each of them were>rolled 100 times simultaneously, then one of them -- somewhere -->might have shown 100 6's in a row. (The actual probability>is not certainty, as it turns out. It's about 1/e.)>So if you do have a die that rolls 100 times in a row and>comes up 6, chances are it's loaded.>How does that follow? The probability of 100 1's is also 1/6^100, so>is the probability of 50 consecutive 4's followed by 50 consecutive>3's, or throwing 123456 ... 1234, or any other combination you can>imagine. Why do some of these combinations imply the dice is loaded>when other's don't?>Just wondering,> How do you load a die in order for it to roll a 1, then a 2, then a > 3, then a 4, then a 5, then a 6? It would take some doing. The best I can think of is a smallmachine that can shift an internal weight after the die comesto a stop. Of course, one can always do the palming trick,switching one loaded die for another undetectably.> Of course the is the dice loaded criterion should be a real-world > one -- if you can make money from a bookie by rolling the die, betting> on its outcome, then it's loaded.> Phil#191, ewill3@earthlink.netIt's still legal to go .sigless.=== === Subject: : Re: Rolling a Dice for 1000 times.In sci.math, Sunny:>The probability of rolling a die and having it come up 6>100 times in a row is 1/6^100, or about 1.53 * 10^-78.>That's about the reciprocal of the number of atoms in the>Universe; if each of them were a die, and each of them were>rolled 100 times simultaneously, then one of them -- somewhere -->might have shown 100 6's in a row. (The actual probability>is not certainty, as it turns out. It's about 1/e.)>So if you do have a die that rolls 100 times in a row and>comes up 6, chances are it's loaded.> How does that follow? The probability of 100 1's is also 1/6^100, so> is the probability of 50 consecutive 4's followed by 50 consecutive> 3's, or throwing 123456 ... 1234, or any other combination you can> imagine. Why do some of these combinations imply the dice is loaded> when other's don't?Actually, that's a good question. I don't reallyhave a good answer beyond the philosophical one and/orprobabilistic one. The die could be fair and true androll up 1 100 times -- it's just extremely improbable.Might as well ask whether the molecules in a 3m x 3m x3m room would all simultaneously (or nearly so) go tothe opposite wall from where you are, and suffocate you.(They wouldn't stay there long; the average speed ofa molecule is 300 m/s or thereabouts, IIRC. Note that3m x 3m x 3m = 27 m^3, or about 1100 moles at standardtemperature and pressure-- for air, that's just under32 kg. By Avogadro's Number that's about 6.6 * 10^26 coinsto flip, die to roll, or other randomizers to play with.)It turns out that the particular sequence that one saw in those100 roles (call it S_i, for i = 1 to 100) has exactly the sameprobability, assuming a fair and true die, as any other sequence.But, if a die is loaded, chances are it's loaded such that acertain face will show up more than the others, and the probabilityfor each throw is the same; therefore, sequences such as all 1'sor all 6's are a lot more likely than a sequence such as6425321621351326126534216534165341614... :-)In a sequence of rolls with a fair die, it is far more probablethat the number of 1's, 2's, etc. in the entire sequence willbe roughly, if not exactly, equal. If I take 16 1's, 2's, 3's,4's, 5's, and 6's (just to make the math easy), that's 96rolls, and the number of possible orderings of thosenumbers is 96! / (16!)^6 = 1.18e70, which compares nicely to6^96 = 5.0 * 10^74 (the total number of rolls), and it turns outthat the probability of getting exactly 16 1's, 2's, etc. inany order is about 1 in 42645, which is a heck of a lot moreprobable than getting exactly 96 1's.But like I said before, it's a probabilistic argument only.> Just wondering,> -Sunny#191, ewill3@earthlink.netIt's still legal to go .sigless.=== === Subject: : Re: Rolling a Dice for 1000 times.> So if you do have a die that rolls 100 times in a row and>> comes up 6, chances are it's loaded.> How does that follow? The probability of 100 1's is also 1/6^100, so> is the probability of 50 consecutive 4's followed by 50 consecutive> 3's, or throwing 123456 ... 1234, or any other combination you can> imagine. Why do some of these combinations imply the dice is loaded> when other's don't?> Actually, that's a good question. I don't really> have a good answer beyond the philosophical one and/or> probabilistic one. The die could be fair and true and> roll up 1 100 times -- it's just extremely improbable.That's it: a weird sequence doesn't tell you the die IS loaded, it gives you a different probability of it being loaded to some non-weird sequence. Given the ways of loading dice, only certain sequences would put the loaded probability higher than the fair one. Examples would be: mostly one number, or two adjacent numbers, or 3 numbers from one corner, or two opposite numbers, or...[exercise for the reader]And of course the Jellyfish backgammon program fixes the dice [ducks, runs]=== === Subject: : Re: Rolling a Dice for 1000 times.> How do you load a die in order for it to roll a 1, then a 2, then a > 3, then a 4, then a 5, then a 6?Well, that's really besides the point, but I'm sure some buddingengineering student could come up with a die that has a mechanisminside to shift the weight appropriately after each throw;P> Of course the is the dice loaded criterion should be a real-world > one -- if you can make money from a bookie by rolling the die, betting> on its outcome, then it's loaded.> PhilWhat I was trying to point out was that the explanation given in theparent post really didn't explain anything. To see if the die is fair,you can device a statistical test on the results of the throws todetermine if the output comes from a discrete, even distributionbetween 1 and 6 with some confidence interval. This is not toodissimilar from the betting approach you proposed. Although you CANmake money from the bookie even if the die is fair, so you can neverreach 100% confidence that the die is fair.-Sunny=== === Subject: : Re: How to show that a polynoial is irreducible ?> Sure *now* you don't see yourself as important and *now* it hardly seems> to matter.> But where might you be in ten years Jesper Hansen?Well, unless Jesper Hansen intends to spend years making the same mistakeover and over, despite being corrected by legions of bright mathematicianswho go out of their way to try to help him understand, and unless he is sostupid as to not take advantage of such help, or at least take off some timefrom declaring how great a genius he is to actually learn basicundergraduate mathematics, no one is going to care in ten years about onesilly little goof he made 10 years ago...he can even make a whole stream ofsilly little goofs while he learns, and he'll be fine.Those who do not have their own section on crank.net have nothing to fearfrom the occasional mistake here.For example, I recently, in discussing the complexity of finding primes,said that finding the next prime after N is in P, because testing forprimality is in P, and the next prime after N is between N and 2N-2, and soif testing is O(N^k), then finding is O(N^(k+1)). Well, that is right, butwhen people talk about being in P for these kind of problems, they mean interms of the number of bits or digits. E.g., linear time would be O(Ln N),not O(N), and prime testing is O(Ln^6 N), and so my proposal for primefinding is O(N Ln^6 N), which is exponential in the number of bits ordigits. Oops.So...should I worry that ten years from now, someone will have a page up=== === Subject: : Re: q: linear algebra / matrices> |>>Hello> | |>>Just taking the Linear algebra course and got a question:> | |>>Is it possible to find the inverse of a matrix A given only: adj(A) ?> |> |>You might like to consider A = -I in odd dimensions.> |>Not sure about even dimensions though.> |> |I think the general answer to your question for nxn matrices over a field> |K is yes if and only if K contains no (n-1)-st roots of 1 other than 1.> |> |Note that if w is an (n-1)-st root of 1, then adj(wI) = adj(I) = I.> |On the other hand, det(A)^(n-1) = det(adj(A)), so det(A) is determined> |by adj(A) up to multiplication by an (n-1)-st root of 1.> i guess i'm hoping that the only reason i can't figure out what> question it is that you're discussing here is because i have no idea> what adj stands for here.adj(A) is read as adjoint of A, the transpose of the co-factor matrix.Derek, your previous answers look promising however I didn't notunderstand thembecause I know basic linear algebra, perhaps you can give me a morepractical solution/explanation?Elias=== === Subject: : Re: Searching for Ptolemy Math Cards> [begin quote]> Polyptolemy> The cards lie on the edges of a regular icosahedron as well as the> edges of a regular dodecahedron. Cards that are alike lie on the> edges of a regular tetrahedron, the faces of a cube and the vertices> of a regular octahedron. Altogether, this reveals the cosets of the> tetrahedral group in the icosahedral group.> In another vein, consider all the points in the scene that lie in an> infinite sequence of nested Polyptolemy cards. These points form a> Cantor set, a most remarkable entity. Cantor sets are completely> disconnected, but uncountable sets.> Amazingly the Canotro set on the surface of the card hasinaccessible points; that is even though the set seems to be> vanishingly dusty, there are points that can be isolated from the> outside of the Cantor set.> The rest is art.> [end quote]> However this card said serving kids since 2248 and Did you know? > Ptolemy mathcards are excellent for unclogging drains!> I'm wondering if anyone else has found any of these peculiar cards.I remember someone showing me a whole deck of these cards to me! Thisone you describe sticks out in my mind since it initiated a discussion.I'll have to ask where she got them. It's very possible thatGoodman-Strauss (as mentioned by someone else) gave them to her orthere was a short chain of passage. I'm sure I was told some more infoabout the cards, but I was paying more attention to my food at thetime.=== === Subject: : Re: Searching for Ptolemy Math Cards>Hi+> I recently found a buisness card sized card in the glove compartment>of a recent rental car in California. On one side it depicted a>strange tesselating image and on the other it said the following:>[begin quote]>Strauss 333>The pattern is one of only 17 possible planar symetries made by>replicating a finite motif; this particular symmetry is completely>determined by the three kinds of points about which the pattern can be>rotated by 120 degrees: the centers of the heads, just off the chins>and between the noses. The notation 333 refers, then, to the three>kinds of 3-fold centers of rotation.>What would happen if you folded the pattern up, somehow, so that all>the noses coincide, all the eye-brows match up, etc? For starts you'd>get a fat wad of paper! SO suppose the pattern is on an infinitely>thin sheet; then after folding you'd have a tidy little surface with>one nose, one eye, etc.>This resulting surface is called an orbifold. THe orbifold for the>333 symmetry turns out to be a triangular pillow shape. Such>orbifolds provide a nice way to classify symmetries.>[end quote]>It also says serving kids since 1953 and Did yo know? The Ptolemy>mathcard co. is a wholly owned subsidiary of the Cadian Borax Corp!> Have you tried a Google search for ptolemy mathcard?Two hits...-----C. GOODMAN-STRAUSS received his Ph.D. at the University of Texas in Austin in 1994, in knot theory, under the supervision of John Luecke. He has been at the University of Arkansas since, with some time spent at the Geometry Center at the University of Minnesota. His current research focus is the study of aperiodic tiles and the complexity of tilings. He is the founder of the world's foremost fictional trading card company, Ptolemy Mathcard, and has recently taken up chainsaw sculpture.-----Curiouser and curiouser...Best, .http://lakeweb.nethttp://ReserveAnalyst.com=== === Subject: : Re: Searching for Ptolemy Math Cards> -----> C. GOODMAN-STRAUSS received his Ph.D. at the University of Texas in > Austin in 1994, in knot theory, under the supervision of John Luecke. He > has been at the University of Arkansas since, with some time spent at > the Geometry Center at the University of Minnesota. His current research > focus is the study of aperiodic tiles and the complexity of tilings. He > is the founder of the world's foremost fictional trading card company, > Ptolemy Mathcard, and has recently taken up chainsaw sculpture.> -----> Curiouser and curiouser...Indeed. So has anyone else seen these things?=== === Subject: : Fourier coefficients processing, HELP!I am applying an FFT on a series of real sound samples and thus getits frequency domain coefficients. Then I compute the magnitude ofeach coefficient to have only real values. Then the spectrum iscomputed by squaring each magnitude. I devide the spectrum to a numberof segments and compute the energy of each segment. I change theenergy of each segment and compute the changing factor by:NewSegmentPower / OriginalSegmentPower. to update the Fouriercoefficient i do the following steps:1) Devide the original coefficient by its original magnitude resultingin the unity complex vector2) Multiply the unity vector with the sqaure root of the newmagnitude.Then I apply the inverse FFT to get a new series of samples. Theproblem is the new samples are complex (imaginary part <> 0). I writethe real part of the samples to a wave file. When I read the sampleand apply the FFT I get a different spectrum because I discrded theimaginary part. What should I do to face this condition?=== === Subject: : Re: Please help with Haar Integration>the meaning of (f : 1_n).>I only copied it from my book...I don't think I understand it either.>Oh, but I do! :-)> Please reply with your findings from Prof. Deitmar and with an explanation> of what the heck is going> through the whole thing, even the first> part about how we can bound f(x) that is continuous with compact support> (compact support here means that> f(x) >= 0 for all x in R, correct?)In my post to professor Deitmar, I forgot to tell him what was the numberof the page that I was talking about. He asked for that information andI have already sent it.Now, compact support *does not mean* that f(x) >= 0 for all x in R. Itmeans that the closure of the set {x | f(x) different from 0} iscompact. Since we're working on the real line, this means that the set{x | f(x) different from 0} is bounded.So you have this continuous function f with compact support. Considerthe intervals [k/n,(k+1)/n], with integer k. There's a finite set ofsuch intervals that contains {x | f(x) different from 0}. Say that thislast set is contained in [p/n,(p + 1)/n] U [(p + 1)/n,(p + 2)/n] U ...... U [(q - 1)/n,q/n]. For each m in {p,p + 1, p + 2,..., q - 1} takex_m = middle point of [m/n,(m + 1)/n] and c_m = max f([m/n,(m + 1)/n]).Then you havef(x) <= sum (c_m 1_n(x_m + x), p<= m < q) (*)because:1) if x < p/n or x > q/n, you have 0 on both sides;2) otherwise, x is on some interval [m/n,(m + 1)/n]. Outside theextreme points, the left side of (*) is f(x) and the right sideis c_m, which is greater that f(x). At the extreme points, theright side is at least c_m, and so it is still greater than f(x).I hope that this helps.Jose Carlos SantosJose Carlos Santos=== === Subject: : Re: Why are there 63360 inches in a mile?>One cubic foot is six and a quarter gallons>That's not what the http://www.onlineconversion.com/volume.htm says:>1 cubic foot = 6.2288355 gallon [UK]- -Ken, __O -<,_ (_)/ (_)Virtuale Saluton.=== === Subject: : Graduate Mathematics ExperienceHello How are you?My first degree is engineering on aeronautics and I became interestedin mathematics and now I am planning to apply for graduate programmein Applied Mathematics. If anyone had the same academic route with me,please share me experiences.Best regards=== === Subject: : Re: Graduate Mathematics ExperienceHello Richard,I will soon be in the same situation. I'm a junior in an Electrical Engineering program, but I plan to go to graduate school in Mathematics. It seems like you might be further along in the process, so I'd like to ask, what are the disadvantages of not having a mathematics undergraduate degree? I'm wondering if there would be any significant benefit in taking the extra year to finish up a math degree after I complete my engineering degree. My main concern is being competitive in applying at good graduate schools.AlexThe only math in the movie, The Matrix, is in the title.(paraphrased from a posting to alt.math.recreational)=== === Subject: : Re: A Paradox of The Central Limit Theorem>> Sorry, I meant lim_{n->infinity}Pr(f(X_n)) not>lim_{n->infinity}f(n)> Really? To quote you again> Well, in my view, the key point of this paradox is that>> lim{n->infinity}Pr{f(n)} = Pr{lim{n->infinity}f(n)} does>> not necessarily hold. How do you say about this?> So you meanlim{n->infinity}Pr{f(n)} = lim_{n->infinity}Pr(f(X_n))>> Non.> I mean lim_{n->infinity}Pr(f(X_n)) = Pr(lim_{n->infinity}f(X_n))> does not necessarily hold true ---- It is a matter of fact though.> I supposed that f denoted some kind of event. If that is so,> then lim_{n->infinity}f(X_n) is a limit of events and must> be an event itself. I didn't know there was a theory of limits> of events --- so what do you mean by lim_{n->infinity}f(X_n)?> lim_{n->infinity}f(X_n)X_n is a random variable depending natural number n.As an example of Pr{lim_{n->infinity}f(X_n)}, I can give the left hand sideof the Strong Law of Large Numbers, viz. Pr{lim_{n->infinity}[X_n = mu].=== === Subject: : Re: A Paradox of The Central Limit Theorem> As an example of Pr{lim_{n->infinity}f(X_n)}, I can give the left hand> side of the Strong Law of Large Numbers, viz. Pr{lim_{n->infinity}[X_n => mu].I still cannot parse this. For s start, the brackets don't match up.It's not the strong law that I know. That states thatP((lim_{n-> infinity} S_n) = mu) = 1where S_n = (X_1+...+X_n)/n and the X_i are indepdendent identicallydistributed random variables with E(|X_i|) finite and E(X_i) = mu.Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: A Paradox of The Central Limit Theorem>> Sorry, I meant lim_{n->infinity}Pr(f(X_n)) not>lim_{n->infinity}f(n)> Really? To quote you again> Well, in my view, the key point of this paradox is that>> lim{n->infinity}Pr{f(n)} = Pr{lim{n->infinity}f(n)} does>> not necessarily hold. How do you say about this?> So you meanlim{n->infinity}Pr{f(n)} = lim_{n->infinity}Pr(f(X_n))>>Non.>I mean lim_{n->infinity}Pr(f(X_n)) = Pr(lim_{n->infinity}f(X_n))>does not necessarily hold true ---- It is a matter of fact though.>I supposed that f denoted some kind of event. If that is so,>then lim_{n->infinity}f(X_n) is a limit of events and must>be an event itself. I didn't know there was a theory of limits>of events --- so what do you mean by lim_{n->infinity}f(X_n)?>lim_{n->infinity}f(X_n)> X_n is a random variable depending natural number n.So what sort of beastie is f then? An event depending on X_n?If so you have written down a limit of a sequence of events.What is such a limit?Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: Analysis question <405594B3.8030002@fc.up.pt> The first problem is :> If f:R->R satisfies f(x+y)=f(x)+f(y) for all x,y in R and lim {x->0} f(x) = L ,> Then prove L = 0.> 2L = lim_{x->0} 2f(x) = lim_{x->0} f(2x) = lim_{x->0} f(x) = L.> 2L = L => L=0.> If f:R->R satisfies f(x+y)=f(x)+f(y) for all x,y in R and continuous at x=c in R,> then How can I prove f(x) is continous on every point x in R?> lim_{x->0} f(x) = lim_{x->0} f((x + c) - c) => = lim_{x->0} f(x + c) + lim_{x->0} f(-c)> = f(c) + f(-c)How is lim(x->0) f(x + c) = f(c) ?Isn't this assuming f continuous at c?> = f(0)> = 0.> So, f is continuous at 0. Now, lim(x->0) f(x) = 0also f(0) = f(0 + 0) = f(0) + f(0); f(0) = 0Thus lim(x->0) f(x) = f(0)f is continuous at 0> lim_{x->a} f(x) = lim_{x->a} f(x - a) + lim_{x->a} f(a) => = f(0) + f(a)> = f(a).=== === Subject: : Re: Analysis question>If f:R->R satisfies f(x+y)=f(x)+f(y) for all x,y in R and continuous at x=c in R,>then How can I prove f(x) is continous on every point x in R?>lim_{x->0} f(x) = lim_{x->0} f((x + c) - c) => = lim_{x->0} f(x + c) + lim_{x->0} f(-c)> = f(c) + f(-c)> How is lim(x->0) f(x + c) = f(c) ?> Isn't this assuming f continuous at c?Yes. I am assuming one of the hypothesis of the problem, which is, asyou can see a few lines above, and continuous at x=cJose Carlos Santos=== === Subject: : Re: Analysis question If f:R->R satisfies f(x+y)=f(x)+f(y) for all x,y in R and> lim {x->0} f(x) = L , Then prove L = 0.lim(x->0) f(x) = lim(x->0) f(2x) = lim(x->0) 2f(x) = 2 lim(x->0) f(x) >> If f:R->R satisfies f(x+y)=f(x)+f(y) for all x,y in R and >> continuous at x=c in R, then How can I prove f(x) is continous >> on every point x in R? >Perhaps this will help: >consider R as a vector space over Q. Then f is an endomorphism. >The following is well-known for vector spaces over R: >- a linear map is continuous in 0 iff it is continuous everywhere >iff f maps bounded sets to bounded sets.More to the point is similar theorem for topological groups, thata linear function continuous somewhere is continuous everywhere.To e-d it out if f continous at y, for all e, some d with for all x |x - y| < d ==> |f(x) - f(y)| < eAssume |x - z| < d, then |x-z+y - y| < d |f(x-z+y) - f(y)| < e |f(x) - f(z)| < e----=== === Subject: : Re: Analysis question>lim_{x->a} f(x) = lim_{x->a} f(x - a) + lim_{x->a} f(a) => = f(0) + f(a)> = f(a).> Doesn't saying that lim x->a f(x-a) = f(0) imply continuity in the first> place?No. Take f(x) = 0 if x is irrational and f(x) = x otherwise. Then, forevery _a_, lim_{x->a} f(x-a) = f(0). But f is continuous only at 0.Jose Carlos Santos=== === Subject: : Re: pi=2.83... ?> When computing arclength, you have to be careful that the pieces you are> adding actually measure arclength. A pixel does not measure arclength.> For example, the line from (0,0) to (100,100) contains approximately 100> pixels. However, the distance between these points is between 141 and> 142 pixel widths.Of course !! By counting +1 for horizontal steps and +sqrt(2) fordiagonal steps, I get the right circumference and thus a goodapproximation of pi.Thank you very much.=== === Subject: : Re: pi=2.83... ?>When computing arclength, you have to be careful that the pieces you are>adding actually measure arclength. A pixel does not measure arclength.>For example, the line from (0,0) to (100,100) contains approximately 100>pixels. However, the distance between these points is between 141 and>142 pixel widths.> Of course !! By counting +1 for horizontal steps and +sqrt(2) for>diagonal steps, I get the right circumference and thus a good>approximation of pi.This will still not give you a correct answer. In the limit, it willyield 'pi' = 8(sqrt(2)-1) = 3.3137... This is closer than your previousestimate of 2 sqrt(2) = 2.828427..., but still not pi.Rob Johnson I'm looking for a solution to the following integral> int x^-1 exp(-(a x +c )^2 + b x + d) dx or int x^-1 exp(ax^2 + b> x + d) dx> You are never going to find an elementary antiderivative because there> is none. The best you can get is a function using the exponential> integral.> EI(x) = Integral{-x, infinity}[(e^-t)/t]dt> I was going to write that, but then concluded that Ei() was probably> not enough, even for integral( exp((x-1)^2)/x ) .The Exponential Integral would be OK as it is implemented in Matlab where Ineed to solve the equation above. I just don't want a numeric solution.However, I think that G. A. Edgar is correct with Ei() not being enough tosolve the problem. Can anybody verify this assumption? Or is there anotherway?Derk=== === Subject: : Re: Antidiagonal, Infinity> Yeah, Ross, when you finish building a bijection between the reals and> the integers, spare some time to find a method of squaring the circle> and if it's not too difficult, an algorithm of solving general> diophantine equations.> ... but first let him prove that there is *no* bijection> between N and Z ;-)> Dirk Vdm> Dirk, you're a troll.> {1, 10, 11, ...} in binary is a completely different set than the one> in decimal.> You should well know that in discussion of decimal that those two> different sets have what I call PC for Post Cantorian> cardinalities that differ. That is just to reuse the word,> cardinality, I am content to not and say that one setminus the other> is non-empty but not vice-versa or that in any sufficiently large> interval of their lowest ceiling set the naturals that there is more> of one than the other or that one set has infinitely many proper> subsets that are proper supersets of the other. I also am quite clear> in that those two sets, or indeed the one set in two different> notations have exactly the same cardinal number, and those two> different sets have different relaxed or nonstandard asymptotic> densities.> Why don't you go back to quietly playing with your marbles.No no, it was the other way around: http://groups.google.com/groups?&q=author%3Amoortel+ross+ marblesDirk Vdm=== === Subject: : Israel behind spanish terrorismComments: This message did not originate from the above address. It was remailed by two or more anonymous mail services. Send complaints of REAL abuse ONLY to remaileradmin at optonline dot nX-Mail2News-Contact: http://80.65.224.85/Why this it not Al-QaedaTimothy McVeighThey have gotten fresh beatings everywhere.And we have done all that thrashing based on PROFESSIONAL CIAINTELLIGENCE.We have done it believing they would be deterred by this beating.No trace of Osama is to be found today.When 911 occurred, Al-Qaeda did not come telling they did it.They tried to hide it, as we think and did a poor job.How could they do such a professional job and conveniently leave thevan to be found? With Arabic tapes of Qoran? To be listening to itjust before the bombing? Why not during bombing with walkman?It is all a setup. A drama. Mossad has done it.Today the victor is always the third party. When two parties fight,the victor is the third.Islam and Christianity fight. Victor is the Israel. That is how theyhave risen to power from nothing.Israelis did a very professional job of blowing up Iraqi reactorinside France.They blew up ships. They spread terrorism on two continents. Africaand Central and South America as well as the birth place of the mostpacifist faith, Buddhism, in Sri Lanka.Didnt Jews under go spanish inquisition? Isn't south america full ofthem? Don't they speak spanish fluently? Are'nt they one of thesmartest people?Let me tell you their history. Hang me by my neck if this is a lie.This is their history. Mel Gibbson should make a movie on this.JOSEPH'S BROTHERSA Jewish producer, who married his step daughter, what is the nameof that sleazy semite, Woody Allen.made a movie:HENNA'S SISTERwhere he seduces the sister of his wife.I say make a movie called Joseph's brothers.The truth is this:Jacob's 10 evil sons conspired to kill their youngbrother Joseph. How in their thirdgeneration of inception, the 10 sons of jacob, conspiredagainst their innocent and righteous young brotherJoseph. This is documented in many scriptures includingtheir own.This is what a movie should be made on. The murder ofJoseph, the son of Jacob and the king of Egypt. withouta spin at the end or subtitle.The movie should show the extent of wickedness needed incollectively staging the murder of a brother and thenreturning to their father Jacob with drama of lies anddeceptive acting.To be sure, the origins of Hollywood acting were laid3000 years ago on the day of murder of Prophet Joseph.and the drama to deceive their own father. who turnedblind in his sadness and crying for joseph.To be sure, the origins of Hollywood acting were laid3000 years ago on the day of murder of Prophet Joseph,just as much of jewish history and rights extend that farin time in every matter.the sons of abraham are also fighting the same way today.with dramas.In this matter, the murderer of Jesus are theZionists. We may distinguish between jews and the torahtrue jews. The minority of torah true jews are not thezionists crazy after material power, money and glory.The zionists or plain jews are the ones who killedjesus. Do not be confused by ambiguous terms likeorthodox or rabbi. Many rabbis and orthodox are secular and torah false, rabid dr strangeloves. The torah true ones arefar and few. One of them is at www.nkusa.org. They mustbe investigated publicly by some non-jewish owned andcontrolled media to make a documentary on them. Theproblem is that US public TV is controlled by the jew, AlJerome. So unless there is a courageous soul like MelGibson, we will not easily see truth on the media for along time and will have to rely on the internet.Today's jews descend in great part from the 10 murderous,deceptive, lying and jealous brothers of Joseph. Only asmall number of them are upright and moral like Josephand Benjamin the righteous sons of Joseph. Those are thetorah true jews. But they are less than 2 out of 12 forthat was the ratio in their third generation. Today it isworse.HISTORICALLY THEY HAVE FAUGHT AND WON BY PITTING THEIR ENEMIESAGAINST EACH OTHER. THERE IS AN UNUSUAL LOVE BETWEEN THESE. ONEIS PAGAN WORSHIPPER OF STATUES. THE OTHER HATES PAGANISM. YETTHEY LOVE EACH OTHER FROM THE HATRED OF THEIR ENEMIES.Tamil terrorists were trained together by Israel.BY WAY OF DECEPTION THOU SHALL WIN - MOSSADhttp://www.biblebelievers.org.au/przion1.htmhttp:// users.one.se/~chribesk/sects/zog/newlight.html-=-This message was posted via two or more anonymous remailing services.=== === Subject: : Re: Israel behind spanish terrorism# Why this it not Al-Qaeda# # Timothy McVeighbe? For a conspiracy theory to have any believability, there must be somekernel of truth. Since Israel wants as many countries as possible beatingon Arabs, this fails that.# Jacob's 10 evil sons conspired to kill their young# brother Joseph. How in their thirdIt's called Joseph and His Technicolour Dream-CoatDerk Gwen http://derkgwen.250free.com/html/index.htmlBut I do believe in this.=== === Subject: : Israel behind spanish terrorismComments: This message did not originate from the above address. It was remailed by two or more anonymous mail services. Send complaints of REAL abuse ONLY to remaileradmin at optonline dot nX-Mail2News-Contact: http://80.65.224.85/Why this it not Al-QaedaTimothy McVeighThey have gotten fresh beatings everywhere.And we have done all that thrashing based on PROFESSIONAL CIAINTELLIGENCE.We have done it believing they would be deterred by this beating.No trace of Osama is to be found today.When 911 occurred, Al-Qaeda did not come telling they did it.They tried to hide it, as we think and did a poor job.How could they do such a professional job and conveniently leave thevan to be found? With Arabic tapes of Qoran? To be listening to itjust before the bombing? Why not during bombing with walkman?It is all a setup. A drama. Mossad has done it.Today the victor is always the third party. When two parties fight,the victor is the third.Islam and Christianity fight. Victor is the Israel. That is how theyhave risen to power from nothing.Israelis did a very professional job of blowing up Iraqi reactorinside France.They blew up ships. They spread terrorism on two continents. Africaand Central and South America as well as the birth place of the mostpacifist faith, Buddhism, in Sri Lanka.Didnt Jews under go spanish inquisition? Isn't south america full ofthem? Don't they speak spanish fluently? Are'nt they one of thesmartest people?Let me tell you their history. Hang me by my neck if this is a lie.This is their history. Mel Gibbson should make a movie on this.JOSEPH'S BROTHERSA Jewish producer, who married his step daughter, what is the nameof that sleazy semite, Woody Allen.made a movie:HENNA'S SISTERwhere he seduces the sister of his wife.I say make a movie called Joseph's brothers.The truth is this:Jacob's 10 evil sons conspired to kill their youngbrother Joseph. How in their thirdgeneration of inception, the 10 sons of jacob, conspiredagainst their innocent and righteous young brotherJoseph. This is documented in many scriptures includingtheir own.This is what a movie should be made on. The murder ofJoseph, the son of Jacob and the king of Egypt. withouta spin at the end or subtitle.The movie should show the extent of wickedness needed incollectively staging the murder of a brother and thenreturning to their father Jacob with drama of lies anddeceptive acting.To be sure, the origins of Hollywood acting were laid3000 years ago on the day of murder of Prophet Joseph.and the drama to deceive their own father. who turnedblind in his sadness and crying for joseph.To be sure, the origins of Hollywood acting were laid3000 years ago on the day of murder of Prophet Joseph,just as much of jewish history and rights extend that farin time in every matter.the sons of abraham are also fighting the same way today.with dramas.In this matter, the murderer of Jesus are theZionists. We may distinguish between jews and the torahtrue jews. The minority of torah true jews are not thezionists crazy after material power, money and glory.The zionists or plain jews are the ones who killedjesus. Do not be confused by ambiguous terms likeorthodox or rabbi. Many rabbis and orthodox are secular and torah false, rabid dr strangeloves. The torah true ones arefar and few. One of them is at www.nkusa.org. They mustbe investigated publicly by some non-jewish owned andcontrolled media to make a documentary on them. Theproblem is that US public TV is controlled by the jew, AlJerome. So unless there is a courageous soul like MelGibson, we will not easily see truth on the media for along time and will have to rely on the internet.Today's jews descend in great part from the 10 murderous,deceptive, lying and jealous brothers of Joseph. Only asmall number of them are upright and moral like Josephand Benjamin the righteous sons of Joseph. Those are thetorah true jews. But they are less than 2 out of 12 forthat was the ratio in their third generation. Today it isworse.HISTORICALLY THEY HAVE FAUGHT AND WON BY PITTING THEIR ENEMIESAGAINST EACH OTHER. THERE IS AN UNUSUAL LOVE BETWEEN THESE. ONEIS PAGAN WORSHIPPER OF STATUES. THE OTHER HATES PAGANISM. YETTHEY LOVE EACH OTHER FROM THE HATRED OF THEIR ENEMIES.Tamil terrorists were trained together by Israel.BY WAY OF DECEPTION THOU SHALL WIN - MOSSADhttp://www.biblebelievers.org.au/przion1.htmhttp:// users.one.se/~chribesk/sects/zog/newlight.html-=-This message was posted via two or more anonymous remailing services.=== === Subject: : Re: inverse trigonometric functions of complex numbers>Anyone know how to take inverse trigonometric functions of complex>numbers/variables using the Google calculator?>Thx.>Andy EppinkYou could try this: for example, with z=1+5i:acos(z): -i * ln((1+5i) + i*sqrt(1-(1+5i)^2))asin(z): -i * ln(i*(1+5i) + sqrt(1-(1+5i)^2))atan(z): i/2 * ln((i+(1+5i))/(i-(1+5i)))Substitute (1+5i) with your number.=== === Subject: : Israel behind spanish terrorismComments: This message did not originate from the above address. It was remailed by two or more anonymous mail services. Send complaints of REAL abuse ONLY to remaileradmin at optonline dot nX-Mail2News-Contact: http://80.65.224.85/Why this it not Al-QaedaTimothy McVeighThey have gotten fresh beatings everywhere.And we have done all that thrashing based on PROFESSIONAL CIAINTELLIGENCE.We have done it believing they would be deterred by this beating.No trace of Osama is to be found today.When 911 occurred, Al-Qaeda did not come telling they did it.They tried to hide it, as we think and did a poor job.How could they do such a professional job and conveniently leave thevan to be found? With Arabic tapes of Qoran? To be listening to itjust before the bombing? Why not during bombing with walkman?It is all a setup. A drama. Mossad has done it.Today the victor is always the third party. When two parties fight,the victor is the third.Islam and Christianity fight. Victor is the Israel. That is how theyhave risen to power from nothing.Israelis did a very professional job of blowing up Iraqi reactorinside France.They blew up ships. They spread terrorism on two continents. Africaand Central and South America as well as the birth place of the mostpacifist faith, Buddhism, in Sri Lanka.Didnt Jews under go spanish inquisition? Isn't south america full ofthem? Don't they speak spanish fluently? Are'nt they one of thesmartest people?Let me tell you their history. Hang me by my neck if this is a lie.This is their history. Mel Gibbson should make a movie on this.JOSEPH'S BROTHERSA Jewish producer, who married his step daughter, what is the nameof that sleazy semite, Woody Allen.made a movie:HENNA'S SISTERwhere he seduces the sister of his wife.I say make a movie called Joseph's brothers.The truth is this:Jacob's 10 evil sons conspired to kill their youngbrother Joseph. How in their thirdgeneration of inception, the 10 sons of jacob, conspiredagainst their innocent and righteous young brotherJoseph. This is documented in many scriptures includingtheir own.This is what a movie should be made on. The murder ofJoseph, the son of Jacob and the king of Egypt. withouta spin at the end or subtitle.The movie should show the extent of wickedness needed incollectively staging the murder of a brother and thenreturning to their father Jacob with drama of lies anddeceptive acting.To be sure, the origins of Hollywood acting were laid3000 years ago on the day of murder of Prophet Joseph.and the drama to deceive their own father. who turnedblind in his sadness and crying for joseph.To be sure, the origins of Hollywood acting were laid3000 years ago on the day of murder of Prophet Joseph,just as much of jewish history and rights extend that farin time in every matter.the sons of abraham are also fighting the same way today.with dramas.In this matter, the murderer of Jesus are theZionists. We may distinguish between jews and the torahtrue jews. The minority of torah true jews are not thezionists crazy after material power, money and glory.The zionists or plain jews are the ones who killedjesus. Do not be confused by ambiguous terms likeorthodox or rabbi. Many rabbis and orthodox are secular and torah false, rabid dr strangeloves. The torah true ones arefar and few. One of them is at www.nkusa.org. They mustbe investigated publicly by some non-jewish owned andcontrolled media to make a documentary on them. Theproblem is that US public TV is controlled by the jew, AlJerome. So unless there is a courageous soul like MelGibson, we will not easily see truth on the media for along time and will have to rely on the internet.Today's jews descend in great part from the 10 murderous,deceptive, lying and jealous brothers of Joseph. Only asmall number of them are upright and moral like Josephand Benjamin the righteous sons of Joseph. Those are thetorah true jews. But they are less than 2 out of 12 forthat was the ratio in their third generation. Today it isworse.HISTORICALLY THEY HAVE FAUGHT AND WON BY PITTING THEIR ENEMIESAGAINST EACH OTHER. THERE IS AN UNUSUAL LOVE BETWEEN THESE. ONEIS PAGAN WORSHIPPER OF STATUES. THE OTHER HATES PAGANISM. YETTHEY LOVE EACH OTHER FROM THE HATRED OF THEIR ENEMIES.Tamil terrorists were trained together by Israel.BY WAY OF DECEPTION THOU SHALL WIN - MOSSADhttp://www.biblebelievers.org.au/przion1.htmhttp:// users.one.se/~chribesk/sects/zog/newlight.html-=-This message was posted via two or more anonymous remailing services.=== === Subject: : re:Israel behind spanish terrorismyes yes, makes a lot of sense, but are you sure they did the Barliebombing. === === Subject: : re:Israel behind spanish terrorismYeah, probably Cantor did it... === === Subject: : Re: re:Israel behind spanish terrorism> Yeah, probably Cantor did it...No of course it wasn't! Don't you people watch the news! A certainguy named K.F. Gauss did it! And it is proven too (by Fermat).=== === Subject: : Re: skewed dualities: functions and sets>> |zzzzzzzzzzzzz ...> as i said, you probably have to learn a fair amount of category theory>> to appreciate this, so you're only demonstrating that you're an idiot.>No, I'm only demonstrating that I recognize a preposterous gasbag when I >see one.>Now is that fair, calling him a preposterous gasbag just because he>used theorems from category theory to explain why f^{-1} does not>commute with intersections?>Hmm, maybe it is.> the last on my list of mathematical disciplines to study?I doubt whether anything useful can be concluded from those replies at all.In the special case of your original case the conceptscategory, functor, limit, colomit and adjoint specialize topartially ordered set, order-preserving map, infimum, supremumand Galois connectionOnce you have seen, how any partially ordered (even preordered) set canbe conceived as a category, the rest is an easy translation of thedefinitions.Given a map f: X ---> Y , the relevant partially ordered sets arethe power sets P(X) and P(Y), where the order is given by inclusion.Then sup=union and inf=intersectionNow f induces maps P(X) ---> P(Y) and P(Y) ---> P(X) viaA --> f[A] := {f(a) | a in A} (for A subset X)B --> f^*[B] := {x in X | f(x) in B} (for A subset X)(f^* instead of f^{-1} mainly for typographical reasons here)Now the basic relation to remember is for any given subsets A of Xand B of Y you havef[A] subset B <==> A subset f^*(B)(1) both f[_] and f^*[_] preserve inclusion,(2) the above relation describes a Galois-connection(3) f[_] preserves unions and f^*[_] preserves intersectionsHowever, in my view this does not explain why f[_] does _not_in general preserve intersections.Also in the context of complete lattices, preserving infima is_equivalent_ to having a right adjoint, so I feel that preservationof suprema by f^*[_] explains that is has a right adjoint, not vice versa.=== === Subject: : Re: skewed dualities: functions and sets|> as i said, you probably have to learn a fair amount of category theory|> to appreciate this, so you're only demonstrating that you're an idiot.||No, I'm only demonstrating that I recognize a preposterous gasbag when I |see one.I guess we have rather different ideas about what counts as preposterousKeith Ramsay=== === Subject: : Re: Royden qn by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i2GEjc120269;>vector space = VS>functions = fcns>You really think that's easier to read than> int_0^1 |x(s)-y(s)| / (1+ |x(s)-y(s)|) ds >??? sorry. >Anyway, this integral does not exist for all x, y in your vector>space. How does the problem actually read?the actual wording of the qn 1) doesn't matter since I figured it out (I was misunderstanding the qn originally) 2) is as I stated previously: X is the VS of all (real) valued fcns on [0,1 ] with + & * (ie. multiplicaion) defined in the usual way. Endow X with the metric topology defined by int_0^1 |x(s)-y(s)| / (1+ |x(s)-y(s)|) ds Show X is not locally convexit's that one some guice would help=== === Subject: : Re: Royden qnIt would be much easier to follow this if (i) you posted replies_as replies_, instead of starting new threads with repliesto posts in old threads, (ii) you found the Enter key on yourkeyboard: one of the lines below extends _way_ past theright edge of the screen. Anyway:>>vector space = VS>>functions = fcnsYou really think that's easier to read than> int_0^1 |x(s)-y(s)| / (1+ |x(s)-y(s)|) ds >??? >sorry. >Anyway, this integral does not exist for all x, y in your vector>space. How does the problem actually read?>the actual wording of the qn 1) doesn't matter since I figured it out (I was misunderstanding the qn originally) >2) is as I stated previously: >X is the VS of all (real) valued fcns on [0,1 ] with + & * (ie. multiplicaion) defined in the usual way. >Endow X with the metric topology defined by > int_0^1 |x(s)-y(s)| / (1+ |x(s)-y(s)|) ds The story on this has not changed since yesterday: You cannot use thatformula to define a metric on X because that integral does not exist for all x, y in X. Either you or the book is leaving out an importantword in the definition of X (I can think of at least two possibilitiesfor what that word might be.)I _suspect_ you're not stating the problem correctly, because you'rerefusing to state exactly what the book says. (Unless the bookactually says fcns in place of functions, etc, in which casemy apologies.)>Show X is not locally convex>it's that one some guice would helpFirst you have to get the _question_ straight.=== === Subject: : hypergeometric function?X-No-archive: yesHallo everybodyI'm having a problem solving a second order ode. The thing has twosingularities at z=pm i and one at z=infty.Can I deduce that the solution is an hypergeometric function?Domenico=== === Subject: : The Math ForumI just got some unsolicited email from the Math Forum, thanking me foremail it claims I sent them and advertising all the good stuff availableat their website. I went to their website and, since my machine doesn'tenable me to send email through a website, I got the address of theirwebmaster, namely webmaster@mathforum.org, and sent email describing theunsolicited email and asking to be taken off their email list, if theyhave one.The response was an automatically generated copy of the same unsolicitedemail message I was complaining about having received. I think that theMath Forum should provide a better way to contact them.I also tried clicking on their suggestion box and found that it includesa field for the sender's email address. Quite possibly it doesn'tdo anything to verify the email address entered in that field.Ultimately, it won't inconvenience me to treat the Math Forum just likeany other internet spammer, but I think that would be unfortunate sinceit seems to be a respectable institution and isn't doing it on purpose.It would be much better if the Math Forum can find some way to clean upits act.Allan Adlerara@zurich.ai.mit.edu***** ** Disclaimer: I am a guest and *not* a member of the MIT Artificial ** Intelligence Lab. My actions and comments do not reflect ** in any way on MIT. Moreover, I am nowhere near the Boston ** metropolitan area. ** *****=== === Subject: : Re: Numerically filtering wave forms from Signalsyour filtering for a frequency, quite low such that it is specified as aperiod (inverse of frequency)Moving average is a low pass filter, which separates (somewhat) thefrequency into high, and low. The highs are suppressed, and the lows remaingrouped together.Use a frequency selective filter, or period selective, FFT etc.Weather will show up nicely on 24 hour.Good luck on stock market.Both have enough variance that the frequency/period component will changewith specific sample.> Hi All,> I'm interested in how the best way to numerically filter a waveform of> a specific period from a signal. For example> (1) Consider we were looking at the temperature in a London as a> function of time. This may be thought of as a superpositioning of> wave forms of various frequencies (I think this was part of Fourier's> Theorem). Clearly there is a substantial contribution from a wave of> period one day. If T(t) is our temperature in London at time t, how> do we numerically find the wave of 24 hour period W24(t) and the> remainder function T(t) such that T(t) = W24(t) + R(t)> (1) Say we had a stock price as a function of time. Say daily close> price over 10 years P(t). If we believed there was a yearly cycle in> it, how would we find this wave form and a remainder function similar> to above.> Hope someone can shed some light on it. Best I have been able to come> up with is that a simple moving average of length T actually filters> out (very roughly) a wave of period T and its harmonics. Hence the> signal less SMA(T) actually gives a very rough approximation of a wave> form of period T. Even better is SMA(T) - SMA(2T) to roughly loose> the harmonics.> Any takers?> Stewart=== === Subject: : Re: Numerically filtering wave forms from Signals> your filtering for a frequency, quite low such that it is specified as a> period (inverse of frequency)Moving average is a low pass filter, which separates (somewhat) the> frequency into high, and low. The highs are suppressed, and the lows remain> grouped together.> Use a frequency selective filter, or period selective, FFT etc.> Weather will show up nicely on 24 hour.> Good luck on stock market.> Both have enough variance that the frequency/period component will change> with specific sample.> Hi All,> I'm interested in how the best way to numerically filter a waveform of> a specific period from a signal. For example> (1) Consider we were looking at the temperature in a London as a> function of time. This may be thought of as a superpositioning of> wave forms of various frequencies (I think this was part of Fourier's> Theorem). Clearly there is a substantial contribution from a wave of> period one day. If T(t) is our temperature in London at time t, how> do we numerically find the wave of 24 hour period W24(t) and the> remainder function T(t) such that T(t) = W24(t) + R(t)> (1) Say we had a stock price as a function of time. Say daily close> price over 10 years P(t). If we believed there was a yearly cycle in> it, how would we find this wave form and a remainder function similar> to above.> Hope someone can shed some light on it. Best I have been able to come> up with is that a simple moving average of length T actually filters> out (very roughly) a wave of period T and its harmonics. Hence the> signal less SMA(T) actually gives a very rough approximation of a wave> form of period T. Even better is SMA(T) - SMA(2T) to roughly loose> the harmonics.> Any takers?> StewartThe usual method to search for periodic content in a time series is tocompute the power density spectrum of the autocorrelation function ofthe signal. The average periodogram of a real data sequence is usuallycomputed by averaging the Fourier transforms of overlapping segments oflength 2^n in the data. n depends on the required frequency resolution.To mitigate boundary effects so-called windowing techniques are appliedto the single segments.There are many books on this topic, e.g.S.D.Stearns, R.A.David: Signal Processing Algorithms using Fortran andC.Prentice Hall, Englewood Cliffs, N.J., 1993On-line book:The Scientist and Engineer's Guide to Digital Signal Processing bySteven W. Smith:http://www.dspguide.com/ e.g. the chapterSpectral Analysishttp://www.dspguide.com/specanal.htmHugo=== === Subject: : Re: Numerically filtering wave forms from Signals> Hi All,> I'm interested in how the best way to numerically filter a waveform of> a specific period from a signal. For example> (1) Consider we were looking at the temperature in a London as a> function of time. This may be thought of as a superpositioning of> wave forms of various frequencies (I think this was part of Fourier's> Theorem). Clearly there is a substantial contribution from a wave of> period one day. If T(t) is our temperature in London at time t, how> do we numerically find the wave of 24 hour period W24(t) and the> remainder function T(t) such that T(t) = W24(t) + R(t)> (1) Say we had a stock price as a function of time. Say daily close> price over 10 years P(t). If we believed there was a yearly cycle in> it, how would we find this wave form and a remainder function similar> to above.> Hope someone can shed some light on it. Best I have been able to come> up with is that a simple moving average of length T actually filters> out (very roughly) a wave of period T and its harmonics. Hence the> signal less SMA(T) actually gives a very rough approximation of a wave> form of period T. Even better is SMA(T) - SMA(2T) to roughly loose> the harmonics.> Any takers?> StewartIf what you are really trying to do is filter out a signal of a period ofone day and look at temperature waveform over a season, then the easiestthing I can think of is to run your data through a low pass filter. Yourmoving filter was essentially a low pass filter, just not a very good one.If you're new to filtering, try a butterworth filter. If you have matlaband the sig toolbox, see:http://www.mathworks.com/access/helpdesk/help/toolbox/ signal/filterd5.shtmlIf you don't, check out:http://kwon3d.com/theory/filtering/butt.htmlI hope this helps in some way.Tim=== === Subject: : Re: Help with Number Pattern by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i2GFNie25342;>What is the next number in this set??> 1 One> 11 One One> 21> 1112> 3112> 211213> 312213> 212223> 114213>31121314>????????=== === Subject: : Re: Who are You Dennis ? by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i2GFNif25337;>My calculus class was challenged to determine and prove which is the>greater of the two: e^pi or pi^e. I have worked on this for quite>some>time, but cannot prove my conclusion. Any suggestions?>DennisHint:Where does x^(1/x) reach a maximum for x > 0?=== === Subject: : Re: Help with Number Pattern by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i2GFNjP25349;>What is the next number in this set??> 1 One> 11 One One> 21 Two One's> 1112 One One, One Two> 3112 Three One's, One Two> 211213 Two Ones, One Two, One Three> 312213 etc> 212223> 114213>31121314>????????=== === Subject: : Re: Probability of choosing N from M - extended. by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i2GFdRf27086;>I can't quite work out the formula for the following. Can anyone>help?> - I have a bag containing B blue balls, R red balls and W white>balls.> - I draw N balls from the bag at random, without replacement, where 0>< N < (B+R+W)> - What is the probability that I have drawn b blue balls, r red ball>and w white balls, where obviously N=b+r+w, as a function of r, b, w,>R, B and W?Hi Nick,should by C(B,b)*C(R,r)*C(W,w)/C(B+R+W,b+r+w)where C(n,k) = n!/k!(n-k)!.Best wishesTorsten.=== === Subject: : Re: Range of Entire function> If f is an entire function that is not a polynomial, then f assumes> every complex number, with one exception, an infinite number of times.> Why every function that's not a polynomial? You can write lots of functions> in terms of an infinite Taylor series, which is like an infinite degree> polynomial, why should this not as a polynomial in that sense?An entire function that is not a polynomial has an essentialsingularity at infinity. A polynomial has at worst a pole at infinity. http://www.math.ohio-state.edu/~edgar/=== === Subject: : Re: Range of Entire function> Robert Israel [NonBreakingSpace].8b.96.87.8c .97.99.95 .93fi.92.9b.93.87>What about the function f(z)=z*exp(z)? exp(z) misses at most {0}, but>0*exp(0)=0, so the range of f doesn't miss any points.>Not necessarily. There's no relation between the points f_1(z) and f_2(z)>miss and the points f_1(z) f_2(z) misses.>You are of course right in general, but in this case I think the range IS C.>See my reply to David.You didn't just say the range was all of C, you said exp(z) misses atmost {0}, but 0*exp(0)=0, so the range of f doesn't miss any pointsIf the fact that z*exp(z) has range C does in fact follow from the fact that exp only misses 0 you should explain _how_ it follows,instead of making cracks about people being allergic to LambertW.>What am I missing here? I only see ONE point being the inverse image of>{0}>and that's neither the null set nor an infinite set.>Exactly true.>Picard's theorem says the inverse image is infinite with at most one>exception.>It doesn't say that the inverse image for that exception can't be finite>and nonempty.>Doh! Thank you Robert. That's what I was looking for. Guess it's time for>some more sleep :*)>>Department of Mathematics http://www.math.ubc.ca/~israel>University of British Columbia>Vancouver, BC, Canada V6T 1Z2=== === Subject: : Re: Range of Entire function>? ?????? ??? ??????>What about the function f(z)=z*exp(z)? exp(z) misses at most {0}, but>0*exp(0)=0, so the range of f doesn't miss any points.>How do you know the range of f is all of C? I'm not saying it's>not, I just don't see why it's obviously true.>The inverse of z*exp(z) is the multivalued LambertW function (denoted by>LW), which is defined everywhere in C and satisfies:>LW(z)*exp(LW(z))=z.>So, given w in C, LW(w) [in fact there are infinitely many values, since LW>is multivalued] is a pre-image of w under f(z)=z*exp(z).>(Then again, I know you are allergic to this function. Don't start asking me>how it's defined and things...)Uh, right.If you'd read the rest of my post you might have found an answer to the questions that you asked. In particular: You seem to be sayingthat LPT implies that the inverse image of a point is either infiniteor empty, you give counterexamples and ask what you're missing.The answer to what you're missing depends on exactly _how_you're deducing that the inverse image is infinite or empty.>Picard's Little Theorem _for f_ (since f is entire also) implies that the>inverse image of any w under f is either an infinite set or the null set>also.>??? How does this follow from Picard's Little Theorem?>http://www.math.niu.edu/~rusin/known-math/95/picard> What are the rest of values (infinitely many of them) in the inverse>image>of {0} under f?>What am I missing here?>=== === Subject: : Squaring homomorphismIs there a way to classify all fields of characteristic 2 for which the squaring map x |--> x^2 is surjective? Up to now, I only know that this is the case for finite fields of characteristic 2 (because the squaring map is an injective homomorphism), and that there are infinite fields of characteristic 2 for which the map is *not* surjective. === === Subject: : Re: Squaring homomorphism> Is there a way to classify> all fields of characteristic 2 for which the squaring map> x |--> x^2> is surjective?Classify? Ambitious. These are called perfect fields ofcharacteristic 2.Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: Squaring homomorphism>Is there a way to classify>all fields of characteristic 2 for which the squaring map>x |--> x^2>is surjective?> Classify? Ambitious. Simple lack of vocabulary. - English is not my mother tongue. > These are called perfect fields of characteristic 2.Thank you very much. - Now I have a keyword to look up in the library. By the way, you woldn't happen to know a *characterization* of these fields which is simpler than the statement above, or would you? Thank you again. Mautsch === === Subject: : Re: Squaring homomorphism>> Is there a way to classify>> all fields of characteristic 2 for which the squaring map>> x |--> x^2>> is surjective?>Classify? Ambitious.> Simple lack of vocabulary. - English is not my mother tongue.>These are called perfect fields of characteristic 2.> Thank you very much. - Now I have a keyword to look up in the library.> By the way, you woldn't happen to know a *characterization*> of these fields which is simpler than the statement above, or would you?As I said in my first messge, I think you are being over-optimistic ifyou are seeking a classification of all such fields.Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : approximation constant: what is the number excluded by sqrt(221)/5 ?It is known that the two first numbers excluded by the first approximationconstant sqrt(5) and sqrt(8) are phi and sqrt(2), but though it is often saidthat the third approximation constant is sqrt(221)/5, I can't find what is thenumber excluded by it ? What is the list ? Please, could you give the10 or 15 first excluded numbers (I am not interested by the constant by itself)or a formula for finding them ? (Please, don't give the formula for finding theapproximation constant; I know it, and it is not what I am looking for).Cordially, nous devons agir comme si la chose qui peut-.90tre ne sera pas devait.90tre (Kant, M.8etaphysique des moeurs, doctrine du droit, II conclusion) Baruchel <.baruchel@laposte.net=== === Subject: : Re: Cantor Paradox :-)> You can list all the possible formulae. Since the subset of those> formulae that satisfy the required conditions is definable you can> define a list of them by induction.> Once you have the list P_n of formulae you produce the list ofdigits> similarily by taking those digits which are proved to fit in place. How do I get, in the language of ZF, from a list of formulas to alist of reals?[/quote:d236a1be1d]For each n there's a unique digit d so that P_n(x) |- that the n-thdigit of x is d. That's all you need to define the diagonal uniquely. === === Subject: : Re: Cantor Paradox :-)> For each n there's a unique digit d so that P_n(x) |- that the n-th> digit of x is d. Why should that be? === === Subject: : Re: Cantor Paradox :-)What formula in ZF corresponds to for every P (in the set offormulas considered), if Pn and Pm then m=n?All we need is to show that there can't be m!=n so that Pn and Pm areprovable for some P, so this isn't a problem. The second proof stillcontains a hole though, because it's not obvious why substituting thenumber I define to its defining formula would yield a provabletautology. === === Subject: : Re: Cantor Paradox :-)> All we need is to show that there can't be m!=n so that Pn and Pm are> provable for some P, so this isn't a problem. Yes it is. Think about it some more.=== === Subject: : Re: Cantor Paradox :-)How do you define that list in the language of ZF?You can list all the possible formulae. Since the subset of thoseformulae that satisfy the required conditions is definable you candefine a list of them by induction.Once you have the list P_n of formulae you produce the list of digitssimilarily by taking those digits which are proved to fit in place.Since we assume that we can prove consistency, this is unambigeous. === === Subject: : Re: Cantor Paradox :-)> You can list all the possible formulae. Since the subset of those> formulae that satisfy the required conditions is definable you can> define a list of them by induction.> Once you have the list P_n of formulae you produce the list of digits> similarily by taking those digits which are proved to fit in place. How do I get, in the language of ZF, from a list of formulas to alist of reals?=== === Subject: : Re: Cantor Paradox :-)> Instead of pairs (P, x) we can consider the set of tripples (P, n,d)> where P satisfies the same assumption and it's provable that Px> implies that the n-th digit of x is d.> Now we can proceed in the same way to define the diagonal number. Proceed how?[/quote:f74aab0c4d]You make a definable list of all the numbers described by the formulaeP_n and take the diagonal.It is descibed by the formula: (n, d) in x if and only if P_n(x)provably implies that the n-th digit of x is 1-d. === === Subject: : Re: Cantor Paradox :-)> You make a definable list of all the numbers described by the formulae> P_n and take the diagonal. How do you define that list in the language of ZF? === === Subject: : Re: Cantor Paradox :-)> It's provable in ZF + {0=1}, but I guess now I'm just being a pest.ZF + {0=1} is inconsistent, whereas ZF + ~ConsisZF is consistent if ZFis consistent. Of course, in an inconsistent system you can provewhatever you want. === === Subject: : re:Cantor Paradox :-)Here's an alternative proof that consistency is unprovable, althoughit might contain some mistakes.Consider all the formulae Px such that |- E!nPn ^ (Pn=>n isnatural) and the length of P is less than (say) 10^6 characters.Suppose we can prove consistency. Then we can prove that Pn and Pmimply m=n for every P. Therefore there are at most finitely manynatural numbers definable by those formulae and thus there is asmallest one that isn't.But we can see that we just carried out the definition of that number,in probably less than 10^6 characters. === === Subject: : Re: Cantor Paradox :-)> Consider all the formulae Px such that |- E!nPn ^ (Pn=>n is> natural) and the length of P is less than (say) 10^6 characters.> Suppose we can prove consistency. Then we can prove that Pn and Pm> imply m=n for every P. What formula in ZF corresponds to for every P (in the set offormulas considered), if Pn and Pm then m=n?=== === Subject: : re:Cantor Paradox :-)Earlier I stated that consistency is undecidable. This is of coursenot always true. For example in ZF + ~Consis ZF consistency isdisprovable.But it certainly isn't provable. === === Subject: : Re: Cantor Paradox :-) Discussion, linux)> Earlier I stated that consistency is undecidable. This is of course> not always true. For example in ZF + ~Consis ZF consistency is> disprovable.> But it certainly isn't provable.It's provable in ZF + {0=1}, but I guess now I'm just being a pest.I think the burden is on those people who think he didn't haveweapons of mass destruction to tell the world where they are. -- White House spokesman Ari Fleischer=== === Subject: : Re: Cantor Paradox :-)> As elaborated by Daryl, this makes no sense. Your argument for the> unprovability of consistency has no substance.It makes no sense, but it certainly has substance.Instead of pairs (P, x) we can consider the set of tripples (P, n, d)where P satisfies the same assumption and it's provable that Pximplies that the n-th digit of x is d.Now we can proceed in the same way to define the diagonal number.It should work now. I hope... === === Subject: : Re: Cantor Paradox :-)> Instead of pairs (P, x) we can consider the set of tripples (P, n, d)> where P satisfies the same assumption and it's provable that Px> implies that the n-th digit of x is d.> Now we can proceed in the same way to define the diagonal number. Proceed how?=== === Subject: : Re: Cantor Paradox :-) Discussion, linux)>The problem is evidently on your end, it seems.> Unfortunately I don't have any idea what to do about it, esp.> considering the fact that I'm not even aware of the problem except> from your complaints.Well, I'd try to determine whether it's my software or usenet.com'sproblem and complain to the appropriate people. That would be astart.Truth is common stuff, ready to your hand, but lies you have to makeyourself, and you can't be sure they are any good until you'veused them --- and then it's too late. John Steinbeck=== === Subject: : Re: Cantor Paradox :-) <87ishcgc0s.fsf@phiwumbda.org On the other hand, *I* sometimes go Bzzt. That must be what caused>(part of) your confusion.> The whole part of your confusion is that you > think other people actually read Kant .Why would I think that? Maybe it's part of your confusion that leadsyou to believe I've read Kant since my undergraduate years.Not all features that are found on the Security tab are designed tohelp make your documents and files more secure. --Microsoft on Officesecurity features (after it was pointed out by a third party that acertain password setting is easily bypassed.) === === Subject: : Re: Cantor Paradox :-)> On the other hand, *I* sometimes go Bzzt. That must be what caused>> (part of) your confusion.> The whole part of your confusion is that you > think other people actually read Kant .> Why would I think that? Maybe it's part of your confusion that leads> you to believe I've read Kant since my undergraduate years. I would think that since you obviously went to a school where reading Kant is an assignment, rather than a case of self-abuse. Possibly even an Aristotilian category of META-Physics.=== === Subject: : Re: Cantor Paradox :-)> Of course I mean that Px is provable and also that it's provable that> x is real. As elaborated by Daryl, this makes no sense. Your argument for theunprovability of consistency has no substance.=== === Subject: : Re: hints for mysterious connection (was: Hints for self taught topology?)>probably the most important thing you should know is that galois>theory and the so-called algebraic topology part of topology (which>is a big part of what munkres's text is about) are, in a sense,>secretly the same subject.> Unfortunately you can only figure out in *what* sense by either> thinking *really* hard, asking someone to explain it to you, or> finding the right book. I think Michio Kuga's Galois' Dream:> Group Theory and Differential Equations might be the most elementary> book that comes close to explaining this stuff.In the meantime, is it possible to give a hint?Many thanks in advance,Herman Jurjus=== === Subject: : Re: hints for mysterious connection (was: Hints for self taught topology?)||>probably the most important thing you should know is that galois|>theory and the so-called algebraic topology part of topology (which|>is a big part of what munkres's text is about) are, in a sense,|>secretly the same subject.||> Unfortunately you can only figure out in *what* sense by either|> thinking *really* hard, asking someone to explain it to you, or|> finding the right book. I think Michio Kuga's Galois' Dream:|> Group Theory and Differential Equations might be the most elementary|> book that comes close to explaining this stuff.||In the meantime, is it possible to give a hint?yes, actually it's pretty easy to give some hints. for example: thegalois groups of galois theory are rather analogous to thefundamental groups of algebraic topology, and in the same way thefield extensions of galois theory are analogous to the coveringspaces of algebraic topology. there are interesting complications tothese analogies, though.[e-mail address jdolan@math.ucr.edu]=== === Subject: : Re: LatLong inside polygon <$yuBEXAXnfVAFwHt@lampsacos.demon.co.uk>ABCD will always be in a plane. This is true not just for squares but any>regular polygon drawn on the surface of a sphere. >Please define what you mean by 'regular polygon' in this (3-D) context.A regular polygon is a polygon with all sides equal and all interior anglesequal.>The original definition of a 'regular polygon' comes from Plane>geometry, in which case your result is too obvious to be>interesting.It's definitely not earth-shattering. I only brought it up because yousuggested that the verteces of the square we were talking about might notlie in a plane.>If you insist on equal lengths of sides and equal angles at every >vertex, your theorem is not true. It might be a 6-gon, zig-zagging>around the equator with rotational symmetry of order 3, for >example. Or it might be a 8-gon with rotation symmetry of order two,>and all edges meeting at right-angles.That's an interesting shape you describe, but it's not regular becauseyou're measuring alternating interior and exterior angles in order to getmatching values. If you don't differentiate between interior and exteriorangles, I can draw you a planar regular 12-gon that looks like this: +--+ | |+--+ +--+| |+--+ +--+ | | +--+For those who can't make out my ASCII figure, it looks like the Red Crosslogo. All 12 angles are 90 degrees, but 4 are 90 measured from the exteriorwhile the other 8 are 90 measured from the interior.>If you insist on an n-gon with rotational symmetry of order n, we>are indeed back at the PLANE definition.>As regards the OP's question, I had assumed that he put square in >quotes, as square because he didn't really mean it. He also said he was only given the diagonal of it and was calculating theother 2 points. MHO is that he might as well make it a real square. I haveproven it is always possible.--Keith Lewis klewis {at} mitre.orgThe above may not (yet) represent the opinions of my employer.=== === Subject: : any properties related with those kinds of groupsHi I have one matrix in complex in the format A is SU(2),A=[x1 x2;-x2' x1] if x1,x2 are chosen from one group SI wonder what kind of properties A has.=== === Subject: : Re: Strange Complex Variables ProblemHi. Sorry I didn't answer earlier. I was busy with a bunch of things,e.g. studying for midterms in other classes.>1. Analytic functions form a Hilbert Space H on a domain D in some>sense.>2. We want to consider the subset J of H with functions whose integral>around the hole is i*2PI and the map F mapping D onto an annulus>(which I assume is centered around the origin).>3. And we want to show that F'/F has an L2 norm (over D) that is <=>the L2 norms of all functions in J.> On general hilbert-space grounds this is the same as saying> that F'/F is orthogonal to all the functions which have integral> 0 around the hole. Oh - I just realized that those are the same> as the functions which are derivatives, and it seems possible> that I see how to do the problem based on that:I don't understand why this is equivalent to F'/F being orthogonal toall functions which have integral 0 around the hole. Can you pleaseexplain this part?By the way, for my personal info -- those functions are derivativesbut not necessarily analytic in the simply-connected domain withoutthe hole, right? Because the integrals around curves inside the holemay be zero.> Without giving everything away: Let's use z* to mean the complex> conjugate of z, and say is the integral of f(g*) over D.> Let O be the set of all f in H such that the integral of f around> the hole is 0.Just the regular f multiplied by g* of course, not f of g* ? > You need to show that = 0 for all f in O. If f is in> O then there exists g analytic in D with f = g', and at least> if D is a nice enough domain g will also lie in your> Hilbert space (possibly g always lies in H, I'm not sure).> So you need to show that = 0. Multiply the integrand> by F'/F', to get |F'|^2 to appear. Now make a change of> variables, using F to rewrite the integral as an integral> over the annulus. Look carefully at what you're integrating> over that annulus. (Note that in the annulus a function> is a derivative if and only if there is no 1/z in its Laurent> expansion...) Looks like it comes out to 0.Alright, I'll check this out.But what do you mean a function is a derivative iff there is no 1/z inits Laurent expansion? I never came across this concept before. Whatabout 1/z^2 in its Laurent expansion?Actualy, I don't think I understand the implications of being aderivative function in complex variables. Can you tell me the basicsof this or refer me to somewhere?> Say D is the unit disk. Let J be the set of all functions f with> f'(0) = 1. Then f(z) = z has the minimal L2 norm in J. I could> make a wild guess on that basis what the Riemann map> was supposed to minimize, but it would just be a wild> guess.Right, that's what he was saying. Minimal L2 norm of all functionswith f'(0) = 1 in the unit disk. Greg MagarshakPS: If you can, please tell me a bit about derivatives and theirimplications.=== === Subject: : Re: Strange Complex Variables Problem>Hi. Sorry I didn't answer earlier. I was busy with a bunch of things,>e.g. studying for midterms in other classes.>1. Analytic functions form a Hilbert Space H on a domain D in some>sense.>2. We want to consider the subset J of H with functions whose integral>around the hole is i*2PI and the map F mapping D onto an annulus>(which I assume is centered around the origin).>3. And we want to show that F'/F has an L2 norm (over D) that is <=>the L2 norms of all functions in J.>On general hilbert-space grounds this is the same as saying>that F'/F is orthogonal to all the functions which have integral>0 around the hole. Oh - I just realized that those are the same>as the functions which are derivatives, and it seems possible>that I see how to do the problem based on that:>I don't understand why this is equivalent to F'/F being orthogonal to>all functions which have integral 0 around the hole. Can you please>explain this part?Well, this is a basic inner-product space thing. Let's see. Let'ssay O is the space of all functions that have integral 0 around thehole.Suppose that F'/F is orthogonal to every f in O. Then for everyf in O we have ||F'/F + f||^2 = ||F'/F||^2 + ||f||^2, and this isminimized when f = 0.Conversely, suppose that f is in O and <> 0.For any scalar c ||F'/F + cf||^2 = ||F'/F||^2 + 2 Re() + |c|^2 ||f||^2,and if that inner product is non-zero then the right sideis larger than ||F'/F||^2 for small c (with the right argument).>By the way, for my personal info -- those functions are derivatives>but not necessarily analytic in the simply-connected domain without>the hole, right? Because the integrals around curves inside the hole>may be zero.We're talking about functions in that Hilbert space. They havedomain D, by definition. >Without giving everything away: Let's use z* to mean the complex>conjugate of z, and say is the integral of f(g*) over D.>Let O be the set of all f in H such that the integral of f around>the hole is 0.>Just the regular f multiplied by g* of course, not f of g* ?Yes - I didn't want to use * for multiplication here. >You need to show that = 0 for all f in O. If f is in>O then there exists g analytic in D with f = g', and at least>if D is a nice enough domain g will also lie in your>Hilbert space (possibly g always lies in H, I'm not sure).>So you need to show that = 0. Multiply the integrand>by F'/F', to get |F'|^2 to appear. Now make a change of>variables, using F to rewrite the integral as an integral>over the annulus. Look carefully at what you're integrating>over that annulus. (Note that in the annulus a function>is a derivative if and only if there is no 1/z in its Laurent>expansion...) Looks like it comes out to 0.>Alright, I'll check this out.>But what do you mean a function is a derivative iff there is no 1/z in>its Laurent expansion? That's a function analytic in an _annnulus_.>I never came across this concept before. What>about 1/z^2 in its Laurent expansion?That's the derivative of -1/z.>Actualy, I don't think I understand the implications of being a>derivative function in complex variables. Can you tell me the basics>of this or refer me to somewhere?Well, I don't know what basics there are to explain - hereit comes up because of how the rest of the proof works.>Say D is the unit disk. Let J be the set of all functions f with>f'(0) = 1. Then f(z) = z has the minimal L2 norm in J. I could>make a wild guess on that basis what the Riemann map>was supposed to minimize, but it would just be a wild>guess.>Right, that's what he was saying. Minimal L2 norm of all functions>with f'(0) = 1 in the unit disk.>Greg Magarshak>PS: If you can, please tell me a bit about derivatives and their>implications.Hmm, I guess what's relevant here is that if g is a derivative(and we use o for composition and * for multiplication) then(g o h) * h' is also a derivative...=== === Subject: : maximal ideals in R[x]I can't figure this out : if I is a maxiaml ideal in a ring R, thenthe ideal generated by I and x in R[x] (it's ring of polynomials) isalso maximal in R[x].Any ideas to approach or a proof would be appreciated.=== === Subject: : Re: maximal ideals in R[x] Adjunct Assistant Professor at the University of Montana.>I can't figure this out : if I is a maxiaml ideal in a ring R, then>the ideal generated by I and x in R[x] (it's ring of polynomials) is>also maximal in R[x].>Any ideas to approach or a proof would be appreciated.What is R[x]/(I,x) ?=========== === Subject: : Re: Calc 2>Hi All,> I'm a college calc 2 student, and I'm hoping for some assistance.Can>someone break down the relationship between series and integrals? Ithought>I was keeping up, but last week my TA used partial fractions to resolve a>series, and that threw me. I asked about it, but his english isn'tgreat,>so I didn't get much from his response. Any help would be greatly>appreciated.> The relationship between series and integrals is kind of a large> topic. Also I suspect that it may be irrelevant here - so he used> partial fractions to evaluate a certain infinite series, that doesn't> mean it had anything to do with integrals.> If you show us the actual problem/solution someone can explain> it to you.We were discussing power series, and the problem was 3/(x^2 + x -2). Hefactored the denom to (x + 2)(x - 1) and used partial fractions to solve.This answers my question. I guess I thought that partial fractions was amethod used for solving integration problems, and that if it was being usedfor series as well then there must be a connection between the two. Afterreading your response I understand that partial fractions is simply amethod, and it can be used to solve several types of problems, and that hewasn't necessarily drawing a connection between series and integrals. Isthis correct?Chris=== === Subject: : Re: Calc 2>Hi All,> I'm a college calc 2 student, and I'm hoping for some assistance.>Can>someone break down the relationship between series and integrals? I>thought>I was keeping up, but last week my TA used partial fractions to resolve a>series, and that threw me. I asked about it, but his english isn't>great,>so I didn't get much from his response. Any help would be greatly>appreciated.>The relationship between series and integrals is kind of a large>topic. Also I suspect that it may be irrelevant here - so he used>partial fractions to evaluate a certain infinite series, that doesn't>mean it had anything to do with integrals.>If you show us the actual problem/solution someone can explain>it to you.>We were discussing power series, and the problem was 3/(x^2 + x -2). He>factored the denom to (x + 2)(x - 1) and used partial fractions to solve.Solve what? (To find the power series for the function about somepoint? Yes, you could certainly use partial fractions for that.)>This answers my question. I guess I thought that partial fractions was a>method used for solving integration problems, It is.>and that if it was being used>for series as well then there must be a connection between the two. Nope.>After>reading your response I understand that partial fractions is simply a>method, and it can be used to solve several types of problems, and that he>wasn't necessarily drawing a connection between series and integrals. Is>this correct?Yes.>Chris=== === Subject: : Help with some funny integrals by support1.mathforum.org (8.11.6/8.11.6/The Math Forum, $Revision: 1.9 primary) id i2GHpxo11181;I have a problem with integration and I was wondering if someone might be able to help me with some problems I have. (Not coursework/homework but self-learning from a thermodynamics book)If:C = (integral between 1 and 2) A dBCalculate C when: AB = const and A1 = 120000, B1 = 44, A2 = 400000AB^1.4 = const and A1 = 2*10^5, B1 = 4, A2 = 0.4*10^5A = const = 1.2 and B1 = 2.4, B2 = 5.2B = const = 3 and A1 = 2.8*10^5, A2 = 1.2*10^5I don't really know where to start with these. For one, the question is ambiguous in the sense that it doesn't define what the 1 and 2 points of the integral are; I can only assume it means B1 and B2. I've had a try at the first one and came up with:AB = kA = k/BC = (integral between B1 and B2) k/B dB = k * (integral between B1 and B2) 1/B dB = k [ln B] (between B1 and B2) = k(ln B2 - ln B1)I'm not sure whether I am along the right track or not. If you're dubious about giving the full answers I'd be happy with hints on how to get to the indefinate integrals. Cheers, Robin=== === Subject: : Re: Determining the Equation of a Shadow Cast onto a Surface>Given a flat circular disk (high-gain antenna), a planar surface (a>solar array), and an arbitrary vector to a point light source (the>Sun), I would like to determine the equation of the resultant shadow>(which would be an ellipse) that would be cast onto the plane.> I have posted an html version of my Maple worksheet for the shadow at:> http://math.asu.edu/~kurtz/shadow.html> --LynnHi Lynn,Oops, I belive there is a small error in the parameterizationequations you posted (the second half of your session). The Sunvector is shown as: sun = [s1, s2, s2] Shouldn't that be [s1, s2,s3]? Since it's a bit difficult for me to figure out which s2'sshould be s3's, is there any way you could please regenerate the finalform of the corrected shadow equation for me?hair) :o)-Rob=== === Subject: : Re: Determining the Equation of a Shadow Cast onto a Surface>Given a flat circular disk (high-gain antenna), a planar surface (a>solar array), and an arbitrary vector to a point light source (the>Sun), I would like to determine the equation of the resultant shadow>(which would be an ellipse) that would be cast onto the plane.> I have posted an html version of my Maple worksheet for the shadow at:> http://math.asu.edu/~kurtz/shadow.html> --LynnHi Lynn,Perfecto! Two questions: 1) Since this is a NASA project, I will berequired to document fully. Would you mind if I publish theseequations? I would be happy to include your name and affiliation asthe source. 2) I don't have Maple. Is there a way I can get thissession in another forma (doc, ppt, pdf, etc?)?-Rob=== === Subject: : Re: fibonacci equation> Dear Joe,> thank you very much for your help,> my problem is to resolve fib(n)+fib(k) = m^2 (n,k >0)> I proposed fib(n)+5=m^2 because I can't found any solution> for k=1,2,3,4,6,7,9,10,11,12,17,36 there are n such that fib(n)+fib(k) is> square.> M.Bouayoun> Ahh, that looks interesting, too. You can reduce that to integral> points on a surface, though there may be better ways to attack it.> Write (say) n=2*n1+n2 and k=2*k1+k2, with n2,k2 being 0 or 1. That> gives 4 cases to consider. For simplicity, I'll write out the case> n2=0 and k2=1.> Define new variables x = u^n1, y = u^n2, z = m, with u=(1+sqrt(5))/2.> Then your equation becomes> a*x^2 - a*x^(-2) + a*u*y^2 - (a/u)*y^(-2) = z^2,> where a = 1/sqrt(5). Clearing denominators gives> a*x^4*y^2 - a*y^2 + a*u*x^2*y^4 - (a/u)*x^2 = x^2*y^2*z^2.> There are conjectures about the existence of integer points for> equations like this (look up Vojta's conjecture, for example). If> this were actually a nonsingular surface of degree 6, then Vojta's> conjecture would say that the integer solutions lie on finitely many> curves. However, this surface is actually singular, so it would be> necessary to do some work to figure out what's going on. Hmmmm....> There are also various generalizations of the ABC conecture to sums> of more than three terms. One of those could probably be applied> directly.> Anyway, the final conclusion, I suspect, will be that the equation> fib(n) + fib(k) = m^2> has at most a finite number of solutions (n,k,m), assuming one of> these standard, but far from proven, conjectures. To prove this> unconditionally, however, seems IMHO to be a difficult task, unless> there's some way that I don't see to reduce the number of variables> from three to two.> Joe SilvermanAnother take on the subject:It is easily shown that x is a Fibonacci number if and only if thereis an integer y such that5x^2 + or - 4 = y^2.Similarly y is a Lucas number if and only if there is an integer xsuch that one of the above two equations is satisfied. (At least forpositive x and y,positive indices for the two sequences, and trivial adjustments forthe moregeneral case).Then Fib(n) + 4 = m^2 gives rise to solutions of the Diophantineequations5(m^2-4)^2 + or - 4 = y^2Since these equations are of the 4'th degree and are probablyirreducible (I don't have time right now to take more than a cursorylook at this), then some version of the Thue/Siegel theorems shouldimmediately imply the finiteness of the number of solutions. I don'trecall seeing this particular problem or any of its obvious analoguesdiscussed anywhere. The field is open.=== === Subject: : Re: fibonacci equation|> In order for fib(n)+5 to be a square mod 8, we need for n to be||Where did mod 8 come from?I picked it. If we're going to consider the equation modulovarious integers, by the Chinese remainder theorem we mightas well pick powers of primes. Squares of even integers areall multiples of 4. Squares of odd integers are all congruentto 1 mod 8. This is not all of the information that its being asquare tells us modulo powers of 2, since we also know thatif it's divisible by 8 it's divisible by 16, and so on, but it seemedlike considering the equation mod 8 would be a good choicesince it eliminates most of the nonsquare residues mod powersof 2.Someone pointed out that from what I said about Fib(-2)+5=4being square, there's no hope to solve the problem with onlycongruences, since n lying in the congruence class of -2 isnever ruled out this way. At least mod 12 it's the only possibility,though.Keith Ramsay=== === Subject: : Re: There needs to be ANSI or ISO math standards> There needs to be ANSI or ISO math standards> some teachers are very anal about symbols and other stuff on tests and > homework[post cut]> if i do not have an = sign for > 4+x=5> 1> when the equal sign is implicit again.Not putting in that equal sign can make a problem suddenly change fromright to wrong. Example:x = -12345678 + 11111111 + 1111111 + 111111 + 11111 + 1111 + 111 + 11+ 1 - 99- 99Using your convention x=-99 and the second line is the statement ofthe fact.BUT if this was a case of wrapping around the margins, then x=-198.That is just a simple example. Take a look at this:0 = (1/4)*( -6*y + s*sqrt[12 - 3*y^2] + t*sqrt[64 - 3*y^2] +y*(-6*s*y)/(2*sqrt[12 - 3*y^2]) + y*(-6*t*y)/(2*sqrt[64 - 3*y^2]) +s*sqrt[12 - 3*y^2]*(-6*t*y)/(2*sqrt[64 - 3*y^2]) + t*sqrt[64 -3*y^2]*(-6*s*y)/(2*sqrt[12 - 3*y^2]) )= -6*y*s*t*sqrt[12 - 3*y^2]*sqrt[64 - 3*y^2] + (12 - 3*y^2)*t*sqrt[64- 3*y^2] + (64 - 3*y^2)*s*sqrt[12 - 3*y^2] + -3*y^2*s*sqrt[12 - 3*y^2]+ -3*y^2*t*sqrt[64 - 3*y^2] + -3*y*(12 - 3*y^2) + -3*y*(64 - 3*y^2)Without that little equal sign at the beginning of the fourth line, itwould be extremely easy to assume all six lines are a singleexpression instead of two equal expressions.> please tell me there is a math ANSI or ISO because math is old and teachers > can be jerks=== === Subject: : Re: There needs to be ANSI or ISO math standardslooksomeone shoudl eb able to write the followingx + 4 + 5 + 6 =x + 9 + 6x + 15without having a = sign behind the second statementbecause solving the problem is reader/math person basedwhat is read or used by the math personotherwise there needs to be a standard from maybe ANSI or ISO*supporting freedom to learn and do math to get an answer, and not supporting teachers who like to make students hate learningand math.=== === Subject: : Re: There needs to be ANSI or ISO math standards> look> someone shoudl eb able to write the following> x + 4 + 5 + 6 => x + 9 + 6> x + 15Plenty of people are able to write that --- doesn't meanit makes sense.Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: There needs to be ANSI or ISO math standards> It makes difference if e is positive, negative or zero. To wit:abs(4-x) < E implicitly means E has to be positive=== === Subject: : Re: There needs to be ANSI or ISO math standards> It makes difference if e is positive, negative or zero. To wit:> abs(4-x) < E implicitly means E has to be positiveApparently you're not actually reading the replies that you're receiving;you're just looking for rubber-stamp yes-men.=== === Subject: : Re: There needs to be ANSI or ISO math standards> Apparently you're not actually reading the replies that you're receiving;> you're just looking for rubber-stamp yes-men.> if you want to flame or project please do it through email not this discussioni am trying to push forward a standard. I want ANSI or ISO to have a standardi want standards=== === Subject: : Re: There needs to be ANSI or ISO math standards> Apparently you're not actually reading the replies that you're receiving;> you're just looking for rubber-stamp yes-men.> if you want to flame or project please do it through email not this > discussion> i am trying to push forward a standard. I want ANSI or ISO to have a > standard> i want standardsYou aren't going to get any, because the only people who want them areundergraduates who aren't doing well in their calculus class, andthose sorts of people don't write ANSI standards. Furthermore, nobodyhere is sympathetic.Nathan=== === Subject: : Re: There needs to be ANSI or ISO math standards>Apparently you're not actually reading the replies that you're>receiving; you're just looking for rubber-stamp yes-men.>>if you want to flame or project please do it through email not this>discussion>i am trying to push forward a standard. I want ANSI or ISO to have a>standard>i want standards> You aren't going to get any, because the only people who want them are> undergraduates who aren't doing well in their calculus class, and> those sorts of people don't write ANSI standards. Furthermore, nobody> here is sympathetic.I doubt whether either of these bodies would adopt grossilliteracy as their standard.Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlLacan, Jacques, 79, 91-92; mistakes his penis for a square root, 88-9Francis Wheen, _How Mumbo-Jumbo Conquered the World_=== === Subject: : Re: There needs to be ANSI or ISO math standards>Apparently you're not actually reading the replies that you're receiving;>you're just looking for rubber-stamp yes-men.if you want to flame or project please do it through email not this >discussion>i am trying to push forward a standard. I want ANSI or ISO to have a >standard>i want standardsThey have standards and your proposal would go directly toNUL:.You are suffering from an overdose of calculator use.At a minimum, get yourself an RP calculator./BAHSubtract a hundred and four for e-mail.=== === Subject: : TestTest. Please Ignore.===Subject: Euclid Paradox :-)Hello :-) I'm sure you're quite familiar with Euclid's proof that P, theset of primes, is finite: specifically, assume the opposite andconstruct a {1, . . . , N} <-> P bijection and find a prime p which isthe image of nothing in {1, . . . , N}. This proof is, of course, flawed: afterall, P is quite finite!To illustrate the flaw, I shall prove that there exists an infinitenumber of strings of typable characters with length less than 125(which, you'll acknowledge at once, is absurd)! Theorem: The set of strings of typable characters with lengthless than 125 is infinite. Proof: It will suffice to merely exhibit an infinite subset, for how cana finite set possibly contain an infinite subset? We claim that such a subset is the set of strings of typablecharacters with length less than 125 which, when read, define a primenumber. (An example of such a string would be: The largest Mersenneprime smaller than one million). Call this subset S. Suppose, forsake of argument, that S is finite. Then we can construct a finite list of all the distinct primesdefined by the strings in S. Now if we pull a Euclid, we end up with a prime p which is not inthe list-- and therefor there is a least prime which cannot be definedusing any string of typable characters with length less than 125. Butthis is absurd: for, we have can define it as The least prime whichcannot be defined by a string of typeable characters with length lessthan one hundred and twenty-five, using a string of typablecharacters with length less than 125! Our only option, then, is to discard our assumption: and concludethat S, and therefor the larger set of ALL strings of typablecharacters with length less than 125, are infinite. Q.E.D. As you see, we have to conclude that either Euclid's proofs areworthless wastes of ink, or there exist an infinite number of stringsof typable characters with length less than 125. I'll let you decide. :-) Your friend, Tyrrell the Great Age 11> Hello :-)> I'm sure you're quite familiar with Cantor's proof that R is> uncountable: specifically, assume the opposite and construct an N<->R> bijection and find a diagonal r which is the image of nothing in N.> This proof is, of course, flawed: afterall, R is quite countable!> To illustrate the flaw, I shall prove that there exists an> uncountable number of finite-length strings of typable characters> (which, you'll acknowledge at once, is absurd)!> Theorem: The set of finite-length strings of typable characters> is uncountable.> Proof: > It will suffice to merely exhibit an uncountable subset, for how> can a countable set possibly contain an uncountable subset?> We claim that such a subset is the set of all finite-length> typable characters which, when read, define a real number. (An example> of such a string would be: The ratio of the circumference to the> diameter of the curve whose equation is x^2+y^2=1). Call this subset> S. Suppose, for sake of argument, that S is countable.> Then we can construct a countable list of all the distinct reals> defined by the strings in S.> Now if we pull a Cantor and go down the diagonal of this list,> adding 1 to each digit (mod 10), we end up with a real r which is not> in the list-- and which therefor cannot be defined using any finite> string of typable characters. But this is absurd: for, we have just> defined it, using a finite string of typable characters!> Our only option, then, is to discard our assumption: and conclude> that S, and therefor the larger set of ALL finite strings of typable> characters, are uncountable. Q.E.D.> As you see, we have to conclude that either Cantor's proofs are> worthless wastes of ink, or there exist an uncountable number of> finite-length strings of typable characters.> I'll let you decide. :-)> Your friend,> Nathan the Great> Age 11=== === Subject: : Re: SCHOENFELDS RANDOM THEOREM> SCHOENFELDS RANDOM THEOREM:> With probability 1, all finite sequences of integers contained by> [n,m] occur infinitely in an infinite sequence of random integers> bound by [n,m].> JSThis is a collorary of Hardy's Theoren 146 (An Introdution to theTheory of Numbers - Fifth Edition . Lr.=== === Subject: : Re: Copyright Issue: Dik Winter publishing my work <49qgi1-5jq.ln1@lexi2.athghost7038suus.net> In sci.math.num-analysis, James Harris> <3c65f87.0403140709.69290995@posting.google.com>:> Unfortunately Dik Winter seems intent on continuing to use my writing> on his webpages without my permission.> My guess is that he feels that there's little I can do about it from> here as he's in the Netherlands.> I need advice on handling this person.> How do you get someone to obey basic laws when they're hiding out in> another country?> Here's one of his webpages:> http://homepages.cwi.nl/~dik/english/mathematics/jsh.html> And no matter how much you hate me, I hope that you understand that> there's a reason why people aren't allowed to just copy someone else's> writing and publish it at their whim.> And part of it is common decency.> What can I do about Dik Winter?> James Harris> Ask him politely to remove it, via certified mail that he can> sign and return. If he refuses, get a lawyer and sue.You misspelt get laughed out of his office.P.A.C. SmithThe vast majority of Iraqis want to live in a peaceful, free world.And we will find these people and we will bring them to justice.=== === Subject: : Re: Copyright Issue: Dik Winter publishing my workIn sci.math.num-analysis, David Moran:>In sci.math.num-analysis, James Harris><3c65f87.0403140709.69290995@ posting.google.com>:>Unfortunately Dik Winter seems intent on continuing to use my writing>on his webpages without my permission.>My guess is that he feels that there's little I can do about it from>here as he's in the Netherlands.>I need advice on handling this person.>How do you get someone to obey basic laws when they're hiding out in>another country?>Here's one of his webpages:>http://homepages.cwi.nl/~dik/english/mathematics/ jsh.html>And no matter how much you hate me, I hope that you understand that>there's a reason why people aren't allowed to just copy someone else's>writing and publish it at their whim.>And part of it is common decency.>What can I do about Dik Winter?>James Harris>Ask him politely to remove it, via certified mail that he can>sign and return. If he refuses, get a lawyer and sue.>-- >#191, ewill3@earthlink.net>It's still legal to go .sigless.> James doesn't know how to do anything politely, however,> he expects everyone else to treat him politely.Well, if he doesn't, he doesn't; that's not *my*problem. :-) I will simply endeavor to politely andaccurately smash his arguments to itty bitty pieces with alarge metaphorical sledgehammer, if I'm able to (obviouslyif my aim is off I might wind up hitting my own foot :-))But I wouldn't want to attack him therewith. Besides,I don't have a real one.If he's worried about Dik Winter's using of his copyrightedmaterial (a slightly weird notion IMO), then he has to showthat he (a) owns that material, and that (b) Dik Winterhas violated copyright thereon in such a way as to transgress a law bearing thereon. Which law, I've no ideaat this time -- and if JSH and Dik Winter are in differentcountries, things get even weirder; I'm not sure whoselaws apply in that case.As it is, from the quick look at the webpage in question,I think Dik's expostulation is clearer than JSH's. :-)> David Moran#191, ewill3@earthlink.netIt's still legal to go .sigless.=== === Subject: : Re: Copyright Issue: Dik Winter publishing my work> Unfortunately Dik Winter seems intent on continuing to use my writing> on his webpages without my permission.> My guess is that he feels that there's little I can do about it from> here as he's in the Netherlands.> You could ask your president to invade the Netherlands.Weapons of Math Destruction. :-p=== === Subject: : Re: the characteristics of differentiation determine it?Originator: israel@math.ubc.ca (Robert Israel)why is the 'usual A' continous?---remove the no for mail=== === Subject: : Re: Are analytic Divisors locally algebraic?Originator: israel@math.ubc.ca (Robert Israel)Altough I don't think that the notations that I used were misleading,I am going to rephrase my question:Let D be the polydisc in C^n centered at 0 and let V= U V_i (union ofV_i) where each V_i={f_i=0} is defined as the zero of an irreducibleand smooth holomorphic function such that f(0)=0.Is there a biholomorphic map G from an open neighborhood of 0 onto anopen neighborhood of 0, such that G(0)=0 and the image of G(V) can bewritten as zero of polynomials?I believe that for n=2 it is not difficoult to show that it is true,but for n>3, I also believe that it is not true. rankine> Let V be an analytic divisor in a polydysc D in C^n (i.e. V={f=0} with> f analytic)> that pass through 0 (i.e. f(0)=0)> Is there (up to shrinking D) a biholomorphism G:D->D, that fixes 0 and> such that the image of V is algebraic (i.e. G(V)={g=0} with g> polynomial) ?> Of course the question is trivial if V is irreducible and smooth at 0.> Your notations are somewhat unclear for me. Do you mean it> as analytic germs (with natural structure through f) or> as analytic sets (with the reduced structure)?> A common formulation would be 'hypersurface singularity'> and your Q means to look at it as analytic algebras,> asking whether they are 'analytifications' of polynomial> ones.> For the natural structure i think there are counter examples.> Sorry, i do not have one, but suggest to look at> ( exp(x) - 1 )^2 - y*exp(x*y)^3 or x^2-y*exp(y*x)^3> (a modification of Neil's parabola x^2-y^3).> Playing with Maple it should be singular in 0 (evaluate> the Hessian) but to decompose exp(x*y) (in polynomials)> should fail.> The other suggestion is to search for 'affine GAGA' or> similar. May be papers of Greuel or Loijenga are also a> good starting point. Or literature on local analytic> algebra or geometry (elder ones will be in French).> ---> remove the no for mail=== === Subject: : Re: Are analytic Divisors locally algebraic?Originator: israel@math.ubc.ca (Robert Israel)>Altough I don't think that the notations that I used were misleading,>I am going to rephrase my question:>Let D be the polydisc in C^n centered at 0 and let V= U V_i (union of>V_i) where each V_i={f_i=0} is defined as the zero of an irreducible>and smooth holomorphic function such that f(0)=0.>Is there a biholomorphic map G from an open neighborhood of 0 onto an>open neighborhood of 0, such that G(0)=0 and the image of G(V) can be>written as zero of polynomials?>I believe that for n=2 it is not difficoult to show that it is true,>but for n>3, I also believe that it is not true.Right you are (and with n>=3, which you perhaps meant to write). The following extended quotation is from Hassler Whitney's paper Local Properties of Analytic Varieties (section 14, p. 240), in _Differential and Combinatorial Topology: A Symposium in Honor of Marston Morse_, Princeton University Press, 1965.---begin quotation---Define V in a neighborhood of 0 in C^3 by the vanishing of f(t,x,y) = xy(y-x)(y-(3+t)x)(y-gamma(t)x),where gamma is a transcendental function, and gamma(0)=4.V has five sheets, intersecting along C_t [by which Whitneymeans the t-axis]. The largest cross ratio of the first foursheets at rho_t=(t,0,0) is 3+t; the largest cross ratio ofthe first three and the last sheet is gamma(t). As in thelast section, each cross ratio is intrinsically related tothe variety at the given point [by which Whitney means it isan invariant of local biholomorphisms]. Hence the set ofpairs (3+t,gamma(t)), and hence the function gamma, is intrinsic to the variety. We show that the variety is notlocally algebraic at any point of C_t. ...---end quotation---You're also right about the case n=2; as Whitney points out,a stronger theorem was proved by Levinson (Bull. Amer. Math.Soc. 66 (1960), 366-368).Lee Rudolph=== === Subject: : Analysis and Applications - Vol 2 No 1Originator: israel@math.ubc.ca (Robert Israel)Analysis and ApplicationsView table-of-contents and abstracts athttp://www.worldscinet.com/aa.htmlContents:Qualitative Behavior Of Solutions Of A Certain Hybrid SystemGeorge SeifertOn Some Classes Of Linearizable Reaction-Convection-DiffusionEquationsM. Rodrigo and M. MimuraThe Stability And Dynamics Of Hot-Spot Solutions To TwoOne-Dimensional Microwave Heating ModelsDavid Iron and Michael J. WardExistence Theorems Of Positive Solutions For Fourth-Order Four-PointBoundary Value ProblemsYuji Liu And Weigao GeAn Improved Biharmonic Model: Incorporating Higher-Order Responses OfThe Plate Bending PhenomenaAlexandre L. MadureiraFor more information, go to http://www.worldscinet.com/aa.html=== === Subject: : Re: Is connected graphs -> P(trees), G|->{spanning trees of G} one-to-one?Originator: bergv@math.uiuc.edu (Maarten Bergvelt)>>Hello everyone!>For a given natural number m, is the map>connected graphs with m edges -> power set of trees,>>G |-> {spanning trees of G}>one-to-one?>Yes, for simple graphs. No, if loops or parallel edges are allowed:>a graph with one loop and one simple edge has the same spanning tree >as a graph with two edges connecting the same 2 vertices. > Oops. I suppose the latter has two spanning trees corresponding to> the two parallel edges. Replace this example with: G1 has a loop at x> and an edge from x to y. While G2 has an edge from x to y and a loop > at y.Actually, this is far from true. Perhaps the simplest example is o o / / o---o o---o---o| | and | /o---o o-----o / o (label the edges so that triangles get the same sets of labels). What really occurs is explained by an old theorem of Whitney, characterizingwhen two graphs have the same matroid.For 3-connected graphs the statement is true, and easy to prove if you havesome matroid concepts at your fingertips.For 2-connected graphs, Whitney's Theorem shows how to transform one graphinto the other.For graphs that are not 2-connected, there must exist a 1-1 correspondencebetween blocks preserving trees.Arnaldo Mandel Departamento de Ci.90ncia da Computa.8d.8bo - Computer Science DepartmentUniversidade de S.8bo Paulo, Bra[sz]il am@ime.usp.brTalvez voc.90 seja um Bright http://the-brights.net Maybe you are a Bright.=== === Subject: : Paper published by Algebraic and Geometric TopologyOriginator: bergv@math.uiuc.edu (Maarten Bergvelt)The following paper has been published:Algebraic and Geometric TopologyURL:http://www.maths.warwick.ac.uk/agt/AGTVol4/agt-4-8 .abs.htmlTitle:Smith Theory for algebraic varietiesAuthor(s):Peter SymondsAbstract:We show how an approach to Smith Theory about group actions onCW-complexes using Bredon cohomology can be adapted to work foralgebraic varieties.Secondary: 14F20Keywords:Smith Theory, Bredon cohomology, coefficient system, varietyReceived: 19 December 2002Author(s) address(es):Department of Mathematics, UMIST PO Box 88, Manchester M60 1QD, UKEmail: Peter.Symonds@umist.ac.uk=== === Subject: : Re: How to solve a polynomial of degree 6 over a ring modulo a compositeOriginator: israel@math.ubc.ca (Robert Israel)Mukesh Kumar Singh schrieb:> Dear Research Community,> I have a generic polynomial equation..> f(t)= t^6 + a. t^5 + b. t^4 + c. t^3 + d. t^2 + e. t + g = 0> I need to solve the above polynomial of degree 6 over a ring modulo a> composite n (n is large of the order of 1024 bbits). Where the factors> of n is unknown and it is hard to find too. I want a solution that> does not amount to factoring n.> I have a finite but large enough set of {a,b,c,d,e,g} for which I need> to know at least one solution.I would try (to modify) the algorithm for roots mod prime (e.g. Henry Cohen,Springer GTM 138, Algo 1.6.1, p.37 or Knuth TAOCP vol. 2). You must checkwhether a division by zero occurs (i.e. you found a factor of n). (sorry if thisis too naive).Contrary to the reply in sci.mathit seems that the solution of a polynomial mod n does not necessarily imply afactorization of n.Trivial exampleFactor f(x)=x^2-4 mod n =(x-2)(x+2)A road to less trivial examples: Fix n s.t. 2^1024< n <2^1025 and choose, e.g. qca. 2^513.f(x)=(x-q)^2-4can still be easily factored (see Cohen), but it is quite unlikely to find afactor of n in doing so.hthKlaus> Can anybody please help?> thanks in advance..> regards,> Mukesh=== === Subject: : This week in the mathematics arXiv (23 Feb - 27 Feb)Originator: bergv@math.uiuc.edu (Maarten Bergvelt)Here are this week's titles in the mathematics arXiv, available at: http://front.math.ucdavis.edu/ http://front.math.ucdavis.edu/submissionsThis week in the mathematics arXiv may be freely redistributedwith attribution and without modification.Titles in the mathematics arXiv (23 Feb - 27 Feb)-------------------------------------------------AC: Commutative Algebra-----------------------math.AC/0402418 I'd like to see a proof or a counterexample --- or, even better, a> reference to a proof or a counterexample --- for the following statement:For every paracompact n-dimensional manifold M which is not compact,> the nth singular cohomology group with integer coefficients, H^n(M;Z),> is trivial.I forgot the assumption connected, obviously. The statement I meant was:For every paracompact connected n-dimensional manifold M which is not compact,the nth singular cohomology group with integer coefficients, H^n(M;Z), is trivial.-- Marc Nardmann(To reply, remove every occurrence of a certain letter from my e-mailaddress.)=== === Subject: : Social Markov process - how to approximate the invariant distribution!Originator: bergv@math.uiuc.edu (Maarten Bergvelt)hi, everyoneMay I ask you a few questions about a Markov process? Suppose the statespace is very large, hence it is almost impossible to write down thetransitionmatrix and solve the line system. Then how to approximate the invariantdistribution of this Markov process?For example, consider that 1000 travelers need to drive from origin r todestination s over a transportation network everyday. Suppose that thereare only two routes connected with r and s. If we assume every traveler'sroute choice follows Markov assumption, that is, today's route choice onlydepends on that of yesterday. If all of them know the actual route traveltimeof yesterday, each of them will follow an i.i.d route choice probabilitymodel.The route chocie model for every traveler is the sameBinomial distribution (1000, p(t-1)), where p(t-1) can be calculatedonce we know the actual travel time of the two routes on day t-1. However,the difficulty is the large dimension of the state space. We can easily seethat thestate space of route flows vary from (0,1000), (1,999), (2,998), ...., to(998,2),(999,1), (1000,0). Since normal distibution is an approximation of Binormialifthe number of trials is large enough, the invariant distribution may berelated tonormal distribution.Is there any other way to approximate the invariant distribution of theMarkovprocess? I heard from others that the convariance matrix can be solved bystochastic diffusion. Do you have any idea bout this?=== === Subject: : Great Lakes K-theory Conference, X, second announcementOriginator: bergv@math.uiuc.edu (Maarten Bergvelt) Great Lakes K-theory Conference, X second announcementDear colleagues, if you know any students or postdocs who might benefit fromthe meeting described here, please encourage them to apply soon, for we haveample support available from the NSF.at the University of Illinois at Urbana-Champaign. The conference is beingorganized locally by Grayson and Randy McCarthy with the help andscientific advice of Eric Friedlander, Rick Jardine, and Manfred Kolster.If you might come, please let Grayson <@math.uiuc.edu> know.This time we are pleased to announce that the conference is generously fundedby the National Science Foundation and the University of Illinois. At leasthalf of the funds made available by the NSF grant must go to US-based graduatestudents, junior faculty, underrepresented groups and/or otherwise unsupportedindividuals, so we are eager to receive applications for financial supportfrom such individuals.To apply for support, please send email to Grayson <@math.uiuc.edu>,estimating your expenses and stating what other monetary support ispotentially available to you. Please include references to publications and/orsolicit a brief email letter of reference from an advisor or mentor. US-basedGraduate students are especially encouraged to apply. For full considerationdon't hesitate to apply after that date, for there may be cancellations or notenough applications.Schedule:We will have six talks, with four on Saturday, May 8, beginning at 11am, andtwo on Sunday, May 9, in the morning, ending by 11:30am. There will be ampletime between talks and at dinner for interaction with each others and thespeakers. Saturday evening we plan to have a buffet dinner catered by a finerestaurant (Milo's) and a party at Grayson's house, with the costsubsidized for students and unsupported postdocs.Speakers:The following mathematicians have agreed to speak. o Gunnar Carlsson, Stanford University, on Derived representation theory and the K-theory of fields o Christian Haesemeyer, University of Illinois at Urbana-Champaign, on Homotopy K-theory of blow-ups. Abstract: We give a proof that Weibel's homotopy invariant K-theory satisfies the expected descent property for arbitrary blow-ups, at least over a base field of characteristic zero. We give applications regarding the negative K-groups of singularities, obtaining partial results on the relevant conjecture of C. Weibel. o Marc Levine, Northeastern University, on The Postnikov tower in motivic stable homotopy theory. Abstract: Voevodsky has defined a version of the Postnikov tower in the motivic stable homotopy category and has shown that the slices in this tower have the natural structure of motives. We will describe how the homotopy coniveau tower used by Friedlander-Suslin in their interpretation and generalization of the Bloch-Lichtenbaum motivic cohomology to K-theory spectral sequence generalizes further to give another construction of Voevodsky's Postnikov tower. This gives a direct relation of the motivic Postnikov tower with the Friedlander-Suslin tower, showing that the slices of the motivic Postnikov tower for K-theory are motivic cohomology. o Steve ell, University of Washington. o Holger Reich, University of Muenster, on The Farrell-Jones Conjecture for higher algebraic K-Theory. Abstract: The Farrell-Jones Conjecture predicts that the algebraic K-Theory of a group ring RG can be expressed in terms of the algebraic K-Theory of the coefficient ring R and homological information about the group. After an introduction to this circle of ideas the talk will report on recent joint work with A. Bartels which builds up on earlier joint work with A. Bartels, T. Farrell and L. Jones. We prove that the Farrell-Jones Conjecture holds in the case where the group is the fundamental group of a closed Riemannian manifold with strictly negative sectional curvature. The result holds for all of K-Theory, in particular for higher K-Theory, and for arbitrary coefficient rings R. o Jonathan M. Rosenberg, University of Maryland, on A K-theory perspective on T-duality in string theory. Abstract: An idea which is now well established in the physics literature is that charges on branes should take values in twisted (topological) K-theory, where the twisting is given by a cohomology class that represents the field strength. It is also expected that T-duality should hold, meaning that the theory on one space-time (with background field) is equivalent to that on another, where tori are replaced by their duals. I will describe recent joint work with Mathai Varghese in which we show how to make this rigorous for space-times which are principal torus bundles. A surprising conclusion is that sometimes the T-dual of a torus bundle turns out to involve non-commutative tori.Housing: o We have reserved (until April 7) a block of 40 rooms at the Illini Union, the building just East of Altgeld Hall. Call 217-333-1241 to make a reservation. Rates are $72-$83 for 1 person, $83-88 for 2 persons, $93 for 3 persons, $97 for 4 persons, and $165 for a suite. Hotel tax is 11% extra. Parking is available nearby. Refer to our conference when making a reservation, and send me email, too, so I can confirm your identity to the hotel, if necessary. o We have also reserved (until April 23) a block of 15 rooms at Hampton Inn at University of Illinois, about 0.2 miles east and then 0.4 miles north of Altgeld Hall, 217-337-1100. Rates are $60 for 1 person and $65 for 2 persons. Refer to our conference when making a reservation, and send me email, too, so I can confirm your identity to the hotel, if necessary. o Anne Martel has a basement bedroom in Champaign about 1.0 miles west of Altgeld Hall, with a trundle bed (that converts into two twin beds) for $45 per night. Call her at 217-398-6686. o See http://www.math.uiuc.edu/~/travel.html for a listing of other hotels.Getting there:See http://www.math.uiuc.edu/~/travel.html for instructions on traveling tothe University of Illinois.Web page:See http://www.math.uiuc.edu/K-theory/Calendar/GL10/ for up to dateinformation.=== === Subject: : Re: Permutational PolynomialX-mailer: epigoneEpigone-thread: voxhemslehOriginator: bergv@math.uiuc.edu (Maarten Bergvelt)Wilfried N.9abauer (the second letter is a German o-Umlaut, i.e. an oaround 1965 (in German). He is, with Hans Lausch, the author of a bookin English, Algebra of polynomials. According to MR, Chapter 3 ofthis book also treats permutation polynomials. PeterFlor (Graz, Austria). === === Subject: : Re: Permutational PolynomialOriginator: israel@math.ubc.ca (Robert Israel)> There's a paper by Rivest titled Permutation Polynomials mod 2^w available> at> theory.lcs.mit.edu/~rivest/ Rivest-PermutationPolynomialsModulo2w.ps> which covers power-of-two moduli pretty thoroughly.It's not about GF(2^n) but about GF(2)^n which is not a field... (I'monly interested in fields :o) ).> By the way, could you give some details about Hermite's criterion as it> applies to this problem? I'm not familiar with it, and a web search didn't> get me any information that I could associate with this problem.You probably have heard of it. It's in Lidl / Niederreiter 's bookFinite fields=== === Subject: : Pencils of Matrix pencils and local maxima of quadratic formsOriginator: bergv@math.uiuc.edu (Maarten Bergvelt)Let A and B be symmetric n x n matrices, with B being non-singular with signature (n-1,1), where n>=4.Consider the problem of finding the maximum of the quadratic form f(u) = u^T A u over a region of the n-2-dimensional manifold S where u^T u = 1 and u^T B u = 0.Clearly, if we let l_i(t) be the ith largest eigenvalue of (A + t B), then:(1) Clearly, the global maximum corresponds to the (unique)minimum of l_1.(2) Not so clearly, any local maximum (in an n-2-dimensional neighborhood of the point in S) corresponds to a local maximum of l_2 where it is neither equal to l_1 or l_3.I would like to show that there is only at most one local maximum ofl_2,in a way which allows numerical determination of its location.Any ideas? (If necessary, we can assume n=4.)