mm-101 === lim delta->0 [f(x+delta)-f(x)]/(delta)^2 exists.> wondering if there are functions that the following limit does exist:> lim delta->0 [f(x+delta)-f(x)] / [(delta)^alpha] exists. where alpha>1> Any references would be nice too.f(x+delta) = f(x) + delta fO(x) + delta^2/2 fOO(x) + o(delta^2)[f(x+delta) - f(x)]/(delta)^2 = fO(x)/delta + fOO(x)/2 + o(1)Therefore, you must have fO(x) = 0 ie f constant as it has been said. Ifthis is not for every x, then you only have to have a null derivative atthe considered points.For your second question, you must have the n-th first derivatives withn = ?or(alpha) equal to zero.-- Nicolas === GR56 grava .88 la saucisse et au marteau: lim delta->0 [f(x+delta)-f(x)]/(delta)^2 exists.> wondering if there are functions that the following limit does exist:> lim delta->0 [f(x+delta)-f(x)] / [(delta)^alpha] exists. where alpha>1> Any references would be nice too.f(x+delta) = f(x) + delta fO(x) + delta^2/2 fOO(x) + o(delta^2)[f(x+delta) - f(x)]/(delta)^2 = fO(x)/delta + fOO(x)/2 + o(1)Therefore, you must have fO(x) = 0 ie f constant as it has been said. If> this is not for every x, then you only have to have a null derivative at> the considered points.For your second question, you must have the n-th first derivatives with> n = ?or(alpha) equal to zero.Careful, careful; he didnOt assume the function was twicedifferentiable, or even once differentiable for that matter. (Althoughit follows.)If the intent is for the limit of (f(x+delta)-f(x))/delta^2 to existfor ALL x, then of course f(x+t) - f(x) f(x+t)-f(x) lim ------------- = lim ----------- * t = 0 t->0 t t->0 t^2for all x, so f is differentiable and fO(x) = 0 identically: so f isconstant.If the intent is to ask whether it is possible for this limit to existfor SOME x, of course it is. Take f(x) = x^3, for example, at x = 0.--Ron Bruck === =About 2 months ago I ran across a problem on MITOs website to find theindefinite integral of a certain function. It was from some problemsolving seminar, and I think it was rated as the hardest problem ofall the problems during the semester. I posted about a while backabout this integral but everybody just said that since MathematicacanOt do it itOs probably not integrable in terms of elementaryfunctions. Well, after about two months of toiling over this problem,I think I might finally have a solution. However, thereOs a fewplaces where, at least to me, things were a little iffy about whetheror not I could do what I was doing. So I want to put my solution andsee if thereOs any ?ws.So, the problem is to find in closed formIntegral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]So, first note two things:1) f(x) = f(1/x) (assuming of course that x is not 0)2) the polynomial in the bottom is a reciprocal polynomialReciprocal polynomials generally can be solved by making asubstitution of the form t = x+1/x. So I use this to my advantagelater.So anyway, first we use obvservation 1 to say that if I =Integral[f(x) dx], then 2I = Integral[f(x) dx] + Integral[f(1/x) dx]In the second integral, let u = 1/x, and it transforms toIntegral[f(x) dx] - Integral[f(u)/u^2 du]Since x is just a placeholder, I replace the xOs with uOs in the firstintegral and get2I = Integral[(1 - 1/u^2)f(u) du]Now, we use the second observation. We already have2I = Integral[(1 - 1/u^2)*(u/Sqrt[u^4+4u^3-6u^2+4u+1]) du]Bringing that u from the numerator into the denominator, we get2I = Integral[(1 - 1/u^2)*(1/Sqrt[u^2+4u-6+4/u+1/u^2]) du]Now we are set up to write the part under the square root as apoloynomial in x+1/x. Indeed, we get2I = Integral[(1 - 1/u^2)*(1/Sqrt[(u+1/u)^2+4(u+1/u)-8]) du]Let v = u+1/u. Then dv = (1-1/u^2) dv, which is perfect since thereOsa (1-1/u^2) sitting right there! So the integral transforms to:2I = Integral[1/Sqrt[v^2 + 4v - 8] dv]Now this integral is easily evaluated as 2I = Log[2 + v + Sqrt[v^2 + 4v - 8]]Substituting v gives 2I = Log[2 + u + 1/u + Sqrt[u^4 + 4u^3 - 6u^2 + 4u + 1]]And substituting x givesI = 0.5*Log[2 + x + 1/x + (1/x^2)Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]]So, is this right? === =Nobody escribi.97 en el mensaje> About 2 months ago I ran across a problem on MITOs website to find the> indefinite integral of a certain function. It was from some problem> solving seminar, and I think it was rated as the hardest problem of> all the problems during the semester. I posted about a while back> about this integral but everybody just said that since Mathematica> canOt do it itOs probably not integrable in terms of elementary> functions. Well, after about two months of toiling over this problem,> I think I might finally have a solution. However, thereOs a few> places where, at least to me, things were a little iffy about whether> or not I could do what I was doing. So I want to put my solution and> see if thereOs any ?ws.>> So, the problem is to find in closed form>> Integral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]>> So, first note two things:>> 1) f(x) = f(1/x) (assuming of course that x is not 0)> 2) the polynomial in the bottom is a reciprocal polynomial>> Reciprocal polynomials generally can be solved by making a> substitution of the form t = x+1/x. So I use this to my advantage> later.>> So anyway, first we use obvservation 1 to say that if I => Integral[f(x) dx], then 2I = Integral[f(x) dx] + Integral[f(1/x) dx]>> In the second integral, let u = 1/x, and it transforms to>> Integral[f(x) dx] - Integral[f(u)/u^2 du]>> Since x is just a placeholder, I replace the xOs with uOs in the first> integral and get>> 2I = Integral[(1 - 1/u^2)f(u) du]>> Now, we use the second observation. We already have>> 2I = Integral[(1 - 1/u^2)*(u/Sqrt[u^4+4u^3-6u^2+4u+1]) du]>> Bringing that u from the numerator into the denominator, we get>> 2I = Integral[(1 - 1/u^2)*(1/Sqrt[u^2+4u-6+4/u+1/u^2]) du]>> Now we are set up to write the part under the square root as a> poloynomial in x+1/x. Indeed, we get>> 2I = Integral[(1 - 1/u^2)*(1/Sqrt[(u+1/u)^2+4(u+1/u)-8]) du]>> Let v = u+1/u. Then dv = (1-1/u^2) dv, which is perfect since thereOs> a (1-1/u^2) sitting right there! So the integral transforms to:>> 2I = Integral[1/Sqrt[v^2 + 4v - 8] dv]>> Now this integral is easily evaluated as>> 2I = Log[2 + v + Sqrt[v^2 + 4v - 8]]>> Substituting v gives>> 2I = Log[2 + u + 1/u + Sqrt[u^4 + 4u^3 - 6u^2 + 4u + 1]]Actually is2I = Log[2 + u + 1/u + Sqrt[u^2 + 4u - 6 + 4/u + 1/u^2]]I = (1/2)Log[2 + x + 1/x + Sqrt[x^2 + 4x - 6 + 4/x + 1/x^2]]I = (1/2)Log[2 + x + 1/x + Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]/x]ButdI/dx = (x^2 - 1)/(2xSqrt[(x^4 + 4x^3 - 6x^2 + 4x + 1]) = (1/2)(1 - 1/x^2)f(x) ???There are something more wrong ...I think that it is in> Integral[f(x) dx] - Integral[f(u)/u^2 du] (#1)>> Since x is just a placeholder, I replace the xOs with uOs in the first> integral and get>> 2I = Integral[(1 - 1/u^2)f(u) du]It would be true if the integrals would be definites. But not if they areindefinites. The first integral in #1 is a function of x, while the secondis a function of u, and x =/= u, actually is x = 1/u. If you replace x by uin the first integral, you must to replace dx by -du/u^2, and you get2I = -2*Integral[f(u)/u^2 du]true, but useless ...-- Ignacio Larrosa Ca.96estroA Coru.96a (Espa.96a)ilarrosaQUITARMAYUSCULAS@mundo-r.com === =[snip]> So anyway, first we use obvservation 1 to say that if I => Integral[f(x) dx], then 2I = Integral[f(x) dx] + Integral[f(1/x) dx]>> In the second integral, let u = 1/x, and it transforms to>> Integral[f(x) dx] - Integral[f(u)/u^2 du]>> Since x is just a placeholder, I replace the xOs with uOs in the first> integral and get>> 2I = Integral[(1 - 1/u^2)f(u) du][snip]This looks wrong. x is in fact not just a placeholder, because you aredoing an indefinite integral. Try writing the integral with explicit limits,say from 1 to X.However, is this step really necessary? You should be able to get by withoutit.-Michael. === =So, the problem is to find in closed formIntegral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]MR1798560 (2002b:11093)van der Poorten, Alfred J.(5-MCQR-NT); Tran, Xuan Chuong(5-MCQR-NT)Quasi-elliptic integrals and periodic continued fractions. (English. English summary)Monatsh. Math. 131 (2000), no. 2, 155--169.11J70 (11Y65)Summary: In this report we detail the following story. Several centuries ago, Abel noticed that the well-known elementary integral $$intfrac{dx}{sqrt{x^2+2bx+c}}=logleft(x+b+sqrt{x^2+2bx+c} right)$$ is just a presage of more surprising integrals of the form $$intfrac{f(x)dx}{sqrt{D(x)}}=logleft(p(x)+q(x)sqrt{D(x)} right).$$ Here $f$ is a polynomial of degree $g$ and the $D$ are certain polynomials of degree $deg D(x)=2g+2$. Specifically, $f(x)=pO(x)/q(x)$ (so $q$ divides $pO$). Note that, morally, one expects such integrals to produce inverse elliptic functions and worse, rather than an innocent logarithm of an algebraic function.Abel went on to study abelian integrals, and it was Chebyshev who explained---using continued fractions---what is going on with these `quasi-ellipticO integrals. Recently, the second author computed all the polynomials $D$ over the rationals of degree 4 that have an $f$ as above. We explain various contexts in which the present issues arise. These contexts include symbolic integration of algebraic functions, the study of units in function fields and, given a suitable polynomial $g$, the consideration of the period length of the continued fraction expansion of the numbers $sqrt{g(n)}$ as $n$ varies over the integers. But the major content of this survey is an introduction to period continued fractions in hyperelliptic---thus quadratic---function fields.Reviewed by M. Mend?s France-- Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlNeedless to say, I had the last laugh. Alan Partridge, _Bouncing Back_ (14 times) === => About 2 months ago I ran across a problem on MITOs website to find the> indefinite integral of a certain function. It was from some problem> solving seminar, and I think it was rated as the hardest problem of> all the problems during the semester. I posted about a while back> about this integral but everybody just said that since Mathematica> canOt do it itOs probably not integrable in terms of elementary> functions. Well, after about two months of toiling over this problem,> I think I might finally have a solution. However, thereOs a few> places where, at least to me, things were a little iffy about whether> or not I could do what I was doing. So I want to put my solution and> see if thereOs any ?ws.So, the problem is to find in closed formIntegral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]So, first note two things:1) f(x) = f(1/x) (assuming of course that x is not 0)> 2) the polynomial in the bottom is a reciprocal polynomialReciprocal polynomials generally can be solved by making a> substitution of the form t = x+1/x. So I use this to my advantage> later.So anyway, first we use obvservation 1 to say that if I => Integral[f(x) dx], then 2I = Integral[f(x) dx] + Integral[f(1/x) dx]In the second integral, let u = 1/x, and it transforms toIntegral[f(x) dx] - Integral[f(u)/u^2 du]Since x is just a placeholder, I replace the xOs with uOs in the first> integral and get2I = Integral[(1 - 1/u^2)f(u) du]Now, we use the second observation. We already have2I = Integral[(1 - 1/u^2)*(u/Sqrt[u^4+4u^3-6u^2+4u+1]) du]Bringing that u from the numerator into the denominator, we get2I = Integral[(1 - 1/u^2)*(1/Sqrt[u^2+4u-6+4/u+1/u^2]) du]Now we are set up to write the part under the square root as a> poloynomial in x+1/x. Indeed, we get2I = Integral[(1 - 1/u^2)*(1/Sqrt[(u+1/u)^2+4(u+1/u)-8]) du]Let v = u+1/u. Then dv = (1-1/u^2) dv, which is perfect since thereOs> a (1-1/u^2) sitting right there! So the integral transforms to:2I = Integral[1/Sqrt[v^2 + 4v - 8] dv]Now this integral is easily evaluated as 2I = Log[2 + v + Sqrt[v^2 + 4v - 8]]Substituting v gives 2I = Log[2 + u + 1/u + Sqrt[u^4 + 4u^3 - 6u^2 + 4u + 1]]And substituting x givesI = 0.5*Log[2 + x + 1/x + (1/x^2)Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]]So, is this right?> Well, I definitely made one mistake in that substituting v should notgive you what I put. I think the final result should beI = 0.5*Log[(x+1)^2 + Sqrt[(x+1)^4-12x^2]] - 0.5*Log[x]If someone could differentiate this using Mathematica and simplify itI would appreciate it. === => About 2 months ago I ran across a problem on MITOs website to find the> indefinite integral of a certain function. It was from some problem> solving seminar, and I think it was rated as the hardest problem of> all the problems during the semester. I posted about a while back> about this integral but everybody just said that since Mathematica> canOt do it itOs probably not integrable in terms of elementary> functions. Well, after about two months of toiling over this problem,> I think I might finally have a solution. However, thereOs a few> places where, at least to me, things were a little iffy about whether> or not I could do what I was doing. So I want to put my solution and> see if thereOs any ?ws.So, the problem is to find in closed formIntegral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]So, first note two things:1) f(x) = f(1/x) (assuming of course that x is not 0)> 2) the polynomial in the bottom is a reciprocal polynomialReciprocal polynomials generally can be solved by making a> substitution of the form t = x+1/x. So I use this to my advantage> later.So anyway, first we use obvservation 1 to say that if I => Integral[f(x) dx], then 2I = Integral[f(x) dx] + Integral[f(1/x) dx]In the second integral, let u = 1/x, and it transforms toIntegral[f(x) dx] - Integral[f(u)/u^2 du]Since x is just a placeholder, I replace the xOs with uOs in the first> integral and get2I = Integral[(1 - 1/u^2)f(u) du]Now, we use the second observation. We already have2I = Integral[(1 - 1/u^2)*(u/Sqrt[u^4+4u^3-6u^2+4u+1]) du]Bringing that u from the numerator into the denominator, we get2I = Integral[(1 - 1/u^2)*(1/Sqrt[u^2+4u-6+4/u+1/u^2]) du]Now we are set up to write the part under the square root as a> poloynomial in x+1/x. Indeed, we get2I = Integral[(1 - 1/u^2)*(1/Sqrt[(u+1/u)^2+4(u+1/u)-8]) du]Let v = u+1/u. Then dv = (1-1/u^2) dv, which is perfect since thereOs> a (1-1/u^2) sitting right there! So the integral transforms to:2I = Integral[1/Sqrt[v^2 + 4v - 8] dv]Now this integral is easily evaluated as 2I = Log[2 + v + Sqrt[v^2 + 4v - 8]]Substituting v gives 2I = Log[2 + u + 1/u + Sqrt[u^4 + 4u^3 - 6u^2 + 4u + 1]]And substituting x givesI = 0.5*Log[2 + x + 1/x + (1/x^2)Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]]So, is this right?> Well, I definitely made one mistake in that substituting v should not> give you what I put. I think the final result should beI = 0.5*Log[(x+1)^2 + Sqrt[(x+1)^4-12x^2]] - 0.5*Log[x]If someone could differentiate this using Mathematica and simplify it> I would appreciate it.The derivative is x^2 - 1 ---------------------------- 2 x sqrt(x^4+4x^3-6x^2+4x+1)--Ron Bruck === =Try this:x^4+4x^3-6x^2+4x+1=(x-a)*(x-b)*(x-c)*(x-d),wherea=-1+1/2 *sqrt(12)+sqrt(3-2*sqrt(3))b=-1+1/2*sqrt(12)-sqrt(3-2*sqrt(3) )c=-1-1/2*sqrt(12)+sqrt(3+2*sqrt(3))d=-1-1/2*sqrt(12)-sqrt(3+ 2*sqrt(3))Thusx/(x^4+4x^3-6x^2+4x+1)=x/((x-a)*(x-b)*(x-c)*( x-d))Try expressing this as a sum of integrable polynomial fractions in x, thenintegrate.> About 2 months ago I ran across a problem on MITOs website to find the> indefinite integral of a certain function. It was from some problem> solving seminar, and I think it was rated as the hardest problem of> all the problems during the semester. I posted about a while back> about this integral but everybody just said that since Mathematica> canOt do it itOs probably not integrable in terms of elementary> functions. Well, after about two months of toiling over this problem,> I think I might finally have a solution. However, thereOs a few> places where, at least to me, things were a little iffy about whether> or not I could do what I was doing. So I want to put my solution and> see if thereOs any ?ws.>> So, the problem is to find in closed form>> Integral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]>> So, first note two things:>> 1) f(x) = f(1/x) (assuming of course that x is not 0)> 2) the polynomial in the bottom is a reciprocal polynomial>> Reciprocal polynomials generally can be solved by making a> substitution of the form t = x+1/x. So I use this to my advantage> later.>> So anyway, first we use obvservation 1 to say that if I => Integral[f(x) dx], then 2I = Integral[f(x) dx] + Integral[f(1/x) dx]>> In the second integral, let u = 1/x, and it transforms to>> Integral[f(x) dx] - Integral[f(u)/u^2 du]>> Since x is just a placeholder, I replace the xOs with uOs in the first> integral and get>> 2I = Integral[(1 - 1/u^2)f(u) du]>> Now, we use the second observation. We already have>> 2I = Integral[(1 - 1/u^2)*(u/Sqrt[u^4+4u^3-6u^2+4u+1]) du]>> Bringing that u from the numerator into the denominator, we get>> 2I = Integral[(1 - 1/u^2)*(1/Sqrt[u^2+4u-6+4/u+1/u^2]) du]>> Now we are set up to write the part under the square root as a> poloynomial in x+1/x. Indeed, we get>> 2I = Integral[(1 - 1/u^2)*(1/Sqrt[(u+1/u)^2+4(u+1/u)-8]) du]>> Let v = u+1/u. Then dv = (1-1/u^2) dv, which is perfect since thereOs> a (1-1/u^2) sitting right there! So the integral transforms to:>> 2I = Integral[1/Sqrt[v^2 + 4v - 8] dv]>> Now this integral is easily evaluated as>> 2I = Log[2 + v + Sqrt[v^2 + 4v - 8]]>> Substituting v gives>> 2I = Log[2 + u + 1/u + Sqrt[u^4 + 4u^3 - 6u^2 + 4u + 1]]>> And substituting x gives>> I = 0.5*Log[2 + x + 1/x + (1/x^2)Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]]>> So, is this right?> === => Try this:> x^4+4x^3-6x^2+4x+1=(x-a)*(x-b)*(x-c)*(x-d),> where> a=-1+1/2*sqrt(12)+sqrt(3-2*sqrt(3))> b=-1+1/2*sqrt(12)-sqrt(3-2*sqrt(3))> c=-1-1/2*sqrt(12)+sqrt(3+2*sqrt(3))> d=-1-1/2*sqrt(12)-sqrt(3+2*sqrt(3))> Thus> x/(x^4+4x^3-6x^2+4x+1)=x/((x-a)*(x-b)*(x-c)*(x-d))> Try expressing this as a sum of integrable polynomial fractions in x, then> integrate.I wish it were so simple. Unfortunately, you need to take the squareroot of that quartic polynomial on the bottom. === =>Try this:>x^4+4x^3-6x^2+4x+1=(x-a)*(x-b)*(x-c)*(x-d),>where>a=-1+ 1/2*sqrt(12)+sqrt(3-2*sqrt(3))>b=-1+1/2*sqrt(12)-sqrt(3-2* sqrt(3))>c=-1-1/2*sqrt(12)+sqrt(3+2*sqrt(3))>d=-1-1/2*sqrt(12 )-sqrt(3+2*sqrt(3))>Thus>x/(x^4+4x^3-6x^2+4x+1)=x/((x-a)*(x-b )*(x-c)*(x-d))>Try expressing this as a sum of integrable polynomial fractions in x, then>integrate.... except that itOs x/sqrt(x^4+4x^3-6x^2+4x+1) that he wants to integrate. According to Maple,> int(x/sqrt((x-a)*(x-b)*(x-c)*(x-d)),x); /(a - c) (x - d)1/2 2 /(c - d) (x - b)1/2 2 (d - a) |---------------| (x - c) |---------------| (a - d) (x - c)/ (b - d) (x - c)/ /(c - d) (x - a)1/2 / |---------------| | (a - d) (x - c)/ /(a - c) (x - d)1/2 /(c - b) (d - a)1/2 c EllipticF(|---------------| , |---------------| ) + (a - d) (x - c)/ (d - b) (c - a)/ (d - c) /(a - c) (x - d)1/2 a - d /(c - b) (d - a)1/2 EllipticPi(|---------------| , -----, |---------------| ) (a - d) (x - c)/ a - c (d - b) (c - a)/ / 1/2 | / ((a - c) (c - d) ((x - a) (x - b) (x - c) (x - d)) ) / /Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === => About 2 months ago I ran across a problem on MITOs website to find the> indefinite integral of a certain function. It was from some problem> solving seminar, and I think it was rated as the hardest problem of> all the problems during the semester. I posted about a while back> about this integral but everybody just said that since Mathematica> canOt do it itOs probably not integrable in terms of elementary> functions.Mathematica 5 gives an answer -- terribly messy -- in closed form in termsof elliptic integrals. I have no idea if that answer is correct or not.> Well, after about two months of toiling over this problem,> I think I might finally have a solution. However, thereOs a few> places where, at least to me, things were a little iffy about whether> or not I could do what I was doing. So I want to put my solution and> see if thereOs any ?ws.>> So, the problem is to find in closed form>> Integral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1][snip]> I = 0.5*Log[2 + x + 1/x + (1/x^2)Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]]>> So, is this right?Have you forgotten how easy such a thing is to check??? Just differentiatewhat you think to be the antiderivative, and see if that result is equalto the integrand!Unfortunately, it seems that you did something wrong...David === => About 2 months ago I ran across a problem on MITOs website to find the> indefinite integral of a certain function. It was from some problem> solving seminar, and I think it was rated as the hardest problem of> all the problems during the semester. I posted about a while back> about this integral but everybody just said that since Mathematica> canOt do it itOs probably not integrable in terms of elementary> functions.Mathematica 5 gives an answer -- terribly messy -- in closed form in terms> of elliptic integrals. I have no idea if that answer is correct or not.Well, after about two months of toiling over this problem,> I think I might finally have a solution. However, thereOs a few> places where, at least to me, things were a little iffy about whether> or not I could do what I was doing. So I want to put my solution and> see if thereOs any ?ws.>> So, the problem is to find in closed form>> Integral[f(x) dx], where f(x) = x/Sqrt[x^4+4x^3-6x^2+4x+1]> [snip]> I = 0.5*Log[2 + x + 1/x + (1/x^2)Sqrt[x^4 + 4x^3 - 6x^2 + 4x + 1]]>> So, is this right?Have you forgotten how easy such a thing is to check??? Just differentiate> what you think to be the antiderivative, and see if that result is equal> to the integrand!Unfortunately, it seems that you did something wrong...DavidI donOt have Mathematica, and itOs a painful function to differentiateand simplify. Of course I could have done it but thereOs alot of roomfor error, and if I make a mistake differentiating IOm likely to thinkthat my answer is wrong, when in fact itOs not. However, you said itis wrong, so I assume you differentiated the result using Mathematicaand didnOt get the same thing. Unfortunate indeed.Is it possible someone can point me to the error? === => Have you forgotten how easy such a thing is to check??? Just differentiate> what you think to be the antiderivative, and see if that result is equal> to the integrand!Unfortunately, it seems that you did something wrong...David> I donOt have Mathematica, and itOs a painful function to differentiate> and simplify. Of course I could have done it but thereOs alot of room> for error, and if I make a mistake differentiating IOm likely to think> that my answer is wrong, when in fact itOs not. However, you said it> is wrong, so I assume you differentiated the result using Mathematica> and didnOt get the same thing. Unfortunate indeed.BTW a simple calculator is a great way to check complicated algebra.Just pick a random value for X and compute the numericalresult at each stage. You can quite quickly track down whichstep contained the error. Numerical differentiation also works quiteeffectively if you have sufficient precision on the calculatorand use common sense in selecting delta-X. === =theorems. Not being able to figure out that proof was really buggingme, IOll sleep better now.>>If F is given consider the sequence of functions (defined on |z| = 1)>F[r](z) = F(rz), where r is a monotone sequence of reals approaching 1, say>r = 1/(1+n) with n a natural number. Since F is continuous F[r](z) uniformly>approaches F(z) as r approaches 1. [This is the point I was missing before ->it holds because the unit circle is a closed set.] Or more precisely: This works because the closed _disk_ is a _compact_> set, which implies that f is uniformly continuous.>Let E/2 be the worst case>error value of |F(z) - F[r](z)|. Since rz lies within the radius of>convergence of F, F converges uniformly there, and we can take a partial sum>P[r](z) that is uniformly within E/2 of F[r](z). This partial sum is a>polynomial in (z) as well as in (rz). For all z on the unit circle |F(z) ->P[r](z)| <= |F(z) - F[r](z)| + |F[r](z) - P[r](z)| < E which goes to zero as>r approaches 1. So the P[r](z) are the desired polynomials in z. [My only>nagging doubt here is that this argument would seem to apply to an F defined>on any circle, not just the unit circle.]Well you can relax, itOs true for any closed disk. (In fact itOs true> in much greater generality, although itOs not so easy to prove; > RungeOs theorem, included in most complex books, gives a> generalization, and MergelyanOs theorem gives the result under> weaker hypotheses yet.)>If the sequence of polynomials is given they converge and therefore form a>Cauchy sequence. The difference between any two of them is an analytic>function and therefore reaches its maxium modulus on the boundary of the>unit disk. So the polynomials form a uniform Cauchy sequence on the closed>unit disk and therefore converge uniformly. [Interestingly none of the math>books I had included CauchyOs criterion for uniform convergence, just>CauchyOs criterion for convergence - too obvious an extension to state>explicitly no doubt. But I did find explicit mention of it on the web.]>>-The polynomials converge uniformly on the closed unit disk and are>continuous, therefore they converge to a continuous function there.>-The polynomials converge uniformly on the open unit disk and are analytic,>therefore they converge to an analytic function there.>>Ian>Been staring at this for hours and canOt seem to find a proof that>>seems needlessly complex or just plain doesnOt work... can someone see>>a simple argument? I would be much appreciated - I donOt even need>>this result for anything but somehow I just canOt let it go.>>Let f be a continuous function on the unit circle T = {|z| = 1}. Show>>that f can be approximated uniformly on T by a sequence of polynomials>>in z if and only if f has an extension F that is continuous on the>>To approximate such an F, consider dilates F[subscripted r](z) =>>F(rz).>>I canOt get either direction to work... if F is given then the hint>>seems to imply that you can obtain the polynomial sequence from the>>power series expansion of F, but how to show uniform convergence in a>>simple way?>> The power series need not converge to F at points of the boundary.>> But thatOs not what the hint suggests - read the hint again...>>If the polynomial sequence is given then itOs easy to use the Cauchy>>integral formula on the polynomials, take the limit, and get F>>analytic (limit of the integral = integral of the limit because of the>>uniform convergence, and analyticity follows from the continuity of>>the limit funciton f). But how to show that F is continuous at points>>on the unit circle?>> DonOt use the Cauchy formula. Use the Maximum Modulus Theorem,>> and look up uniform convergence and Cauchy sequence in a book>> on adbanced calculus.>>I found this in Complex Analysis by Gamelin, section V.4, problem 14.>> David C. Ullrich>> David C. Ullrich === =Two thoughts on why e is good, and a limerick:(1) If we could choose an irrational number as ourbase (ie instead of the usual 10 or 2 for binary),then e would be the most efficient. Why?An n-symbol string in base m can represent m^n differentnumbers, and to do so we use n*m different symbols(m letters, but each letter can be n differentpositions). So if we write the size of therepresented space (m^n) as a function of the numberof different symbols k=m*n, we getf(k) = m^(k/m) = (m^(1/m))^k.I like to think of the number (m^(1/m)) ascapturing the efficiency of thestandard base-m type encoding. In the integers,3 maximizes this as 1.4422... But if we usesome calculus, the global maximum is actually ate, with a value of 1.4446...In other words, our efficiency is maximized at e.This argument is my own, but IOm sure it has beendone better elsewhere, because everything I thinkI have thatOs even slightly original turns out that way...(2) One of the most beautiful theorems of modernmathematics: the central limit theorem. Usuallypeople think of it as only applying to probability, sinceit is easiest to interpret in that realm. But itview, you could declare the presence of e in thestatement of CLT to be a consequence of Fourieranalysis (and sort of from EulerOs formula e^(ix) =cos(x) + i sin(x)), but this is a bit of an over-simplification.limit theorem; so the best elementary idea of it thatI can give is that there is a single function,something like e^(-x^2/2) (times a constant), whichrepresents the limiting behavior of virtually _any_ functionwhich is randomly sampled and then averaged. I knowthatOs a bad description, but itOs a start.Finally, the limerick (written by me :)My favorite number is eit compounds continuously;if you raise it to pimultiplied by i,negative one it will be.-Tyler === =Part IINote this is all constructive criticism of HalOs ideas on metric engineering.Excerpts from Puthoff & IbisonsH.E. PUTHOFF*, S.R. LITTLE AND M. IBISONInstitute for Advanced Studies at Austin, 4030 West Braker Lane, Suite 300, Austin, Texas 78759-5329, USA.with my comments.3. The Quantum Vacuum3.1 Zero-Point Energy (ZPE) BackgroundQuantum theory tells us that so-called empty space is not truly empty, but is the seat of myriad energetic quantum processes. Specifically, quantum field theory tells us that, even in empty space, fields (e.g., the electromagnetic field) continuously ?ctuate about their zero baseline values.So far, so good. However IMHO it is the QED PV virtual electron-positron zero point vacuum ?ctuations that dominate the low energy effective macro-quantum field theory out of which EinsteinOs gravity together with exotic vacuum unified dark energy/matter fields co-emerge like love and marriage all together as phase and amplitude modulation patterns, respectively, of the vacuum coherence field that is formed by the attractive BCS exchange of virtual photons between the virtual electron-positron pairs all inside the vacuum. Note that Hal makes no reference at all to the new discovery in precision cosmology of dark energy as being relevant to his Quixotic Ahabian quest in search of for the vacuum wind. :-)The energy associated with these ?ctuations is called zero point energy (ZPE), re?cting the fact that such activity remains even at a temperature of absolute zero. Such a concept is almost certain to have profound implications for future space travel, as we will now discuss.Agreed.When a hypothetical ZPE-powered spaceship strains against gravity and inertia ...ThatOs a strange way of putting it. The local net random micro-quantu zero point stress-energy density tensor field isTuv(Exotic Vacuum) = (String Tension)/ZPEguvusing Ed WittenOs natural units h = c = k(Boltzmann) = 1Tuv(Exotic Vacuum) = (String Tension)^2[(String Tension)^3/2|Vacuum Coherence|^2 -1]guvWhat is wrong with PuthoffOs paradigm is that he has no idea of Vacuum Coherence in his informal thinking nor formalized in his mathematics.The zero point energy density is Too and I use the 3 GR sign conventions in whichToo(Exotic Vacuum) > 0 means strongly anti-gravity negative pressure dark energy since the general equation of state(pressure) = w(energy density)reduces to w = -1 for ALL zero point quantum fields of all spins.Too(Exotic Vacuum) < 0 means strongly gravitating positive pressure dark matter.Therefore dark energy needs(String Tension)^3/2|Vacuum Coherence|^2 > 1Dark matter needs(String Tension)^3/2|Vacuum Coherence|^2 < 1Where the critical Vacuum Coherence corresponding to zero Einstein Cosmological Constant of the non-exotic vacuum in the large-scale FRW metric is(String Tension)^3/2|Vacuum Coherence|^2 = 1Or|Vacuum Coherence|*^2 = (String Tension)^-3/2The Einstein exotic vacuum local geometrodynamic field equation is thenTuv(Induced Time and Space Warps) + Tuv(Exotic Vacuum) ~ 0The total covariant 4-divergence vanishes conserving total local stress-energy Einstein current density.Unlike 1915 geometrodynamics, the Bianchi identities break down so that the two pieces of the divergence are not separately zero!Only the sum is zero. This is necessary for practical soft metric engineering of the Tech Gnostic Underground Stream inside the vacuum.That is,Tuv(Induced Space and Time Warps)^;v + Tuv(Exotic Vacuum)^;v = 0This is the first small step for Mankind leading to The Right Stuff to Make Star Trek Real.See my lecture in Time Travel: The Art of the Possible Disk 2 of Paramount Pictures DVDSpecial CollectorOs Edition of Star Trek IV: The Voyage Home indeed! ;-)*Before you read on click on this! Turn the volume up on your sound.Sarfatti pitches to Puthoff at bat in the World Series :-)http://www.niehs.nih.gov/kids/lyrics/ballgame.htmthere are three elements of the equation that the ZPE technology could in principle address: (1) a decoupling from gravity,NO! We want just the opposite! Big error of strategic thinking!The Question is: What is The Question?Here Hal & Co ask a wrong question IMHO.STRIKE ONE!(2) a reduction of inertiaNO! Ditto. ThatOs like preventing your car from being stolen by blowing it up if it is broken into!STRIKE TWO!or (3) the generation of energy to overcome both.NO, NO, NO a zillion times NO! ;-)ThatOs the Brute Force approach.That is notThe Tao Chi of ET!STRIKE THREE!YouOre Out!Take me out to the ball game ....3.2 GravityWith regard to a ZPE basis for gravity, the Russian physicist Andrei Sakharov was the first to propose that in a certain sense gravitation is not a fundamental interaction at all, but rather an induced effect brought about by changes in the quantum-?ctuation energy of the vacuum when matter is presentYes, this is essentially correct and is precisely what my theory is all about. The details are inhttp://qedcorp.com/APS/EmergentGravity.doc or http://qedcorp.com/APS/EmergentGravity.doc (smaller file)to be continued.Engineering the Zero-Point Field and Polarizable Vacuum for Interstellar Flight1. IntroductionThe concept of engineering the vacuum found its first expression in the mainstream physics literature when it was introduced by T. D. Lee in There he stated:The experimental method to alter the properties of the vacuum may be called vacuum engineering.... If indeed we are able to alter the vacuum, then we may encounter some new phenomena, totally unexpected.This legitimization of the vacuum engineering concept was based on the recognition that the vacuum is characterized by parameters and structure that leave no doubt that it constitutes an energetic medium in its own right. Foremost among these are its properties that (1) within the and field ?ctuations, and (2) within the context of general relativity the vacuum is the seat of a spacetime structure (metric) that encodes the distribution of matter and energy. Indeed, on the ?leaf of a book of essays by Einstein and others on the properties of the vacuum we find the statement The vacuum is fast emerging as the central structure of modern physics [3].Given the known characteristics of the vacuum, one might reasonably inquire as to why it is not immediately obvious how to catalyze robust interactions of the type sought for space-?ght applications. To begin, in the case of quantum ?ctuations there are uncertainties that remain to be clarified regarding global thermodynamic and energy constraints. Furthermore, the energetic components of potential utility involve very small-wavelength, high-frequency fields and thus resist facile engineering solutions.This last remark may not be correct in general, although it is correct within the framework Puthoff is pursuing i.e. using the stress-energy density of the electromagnetic field to attempt to directly warp space-time geometry with practical utility. Such a brute-force approach is hopeless and a waste of effort IMHO because Einsteins equation in this case is simplyInduced Space-Time Warp = (Applied EM Stress-Energy Density)/(G-String Tension)The G-String Tension is 10^19Gev per 10^-33 cm, which is simply too stiff! One would need a way to lower the G-String-Tension, for example an M Theory that yields something like:G*-String Tension = e^-(r*/Lp)^?(G-String Tension)Where r* = compactification scale of extra-dimensions of hyperspace beyond 4-D space-time andLp^2 = hG/c^3 = 1/(G-String Tension) for h = c = 1Puthoff alludes to this barrier in his next remark:With regard to perturbation of the space-time metric, the required energy densities exceed by many orders of magnitude values achievable with existing engineering techniques. Nonetheless, we can examine the constraints, possibilities and implications under the expectation that as technology matures, felicitous means may be found that permit the exploitation of the enormous, as-yet-untapped potential of so-called empty space.This is the problem that Hal goes into denial and wishing about. There is no way that will brute-force approach will work in any practical way. The UFOs do not use high-energy EM field densities and Hal is primarily interested in the UFOs. That should tell him right away that he is pursuing the wrong path to solve the problem.2. Propellantless Propulsion2.1 Global ConstraintRegardless of the mechanisms that might be entertained with regard to propellantless or field propulsion of a spaceship, there exist certain constraints that can be easily overlooked but must be taken into consideration. A central one is that, because of the law of conservation of momentum, the center of mass-energy (CM) of an initially stationary isolated system cannot change its position if not acted upon by outside forces. This means that propellantless or field propulsion, whatever form it takes, is constrained to involve coupling to the external universe in such a way that the displacement Engineering the Zero-Point Field and Polarizable Vacuum for Interstellar FlightIt has been known since the late 1950s how to circumvent this problem provided one has exotic stuff with a strong enough negative pressure to provide what Herman Bondi called negative matter in the late 1950s and Kip Thorne called exotic matter in the late 1980s in his traversable wormhole time travel papers with additional work by Igor Novikov and others. Robert Forward summarized Bondis early work in a paper written in the early 1990s. More details are to be found inWe now know since 1999 from Type 1a supernova data showing the acceleration of the expansion speed of the Universe that approximately 3/4 of all the large-scale stuff of the Universe is exotic vacuum anti-gravitating dark energy with a strong negative zero point pressure that is equal and opposite to the positive zero point energy density. This fact is the key to practical metric engineering of the vacuum that Puthoff et-al completely misses. The modified vacuum Einstein equation isTuv(Geometry) + Tuv(Exotic Vacuum) = 0Where Tuv is the local stress-energy density tensor under the Einstein DIFF(4) symmetry group.Tuv(Geometry) = (String Tension)Guv(Geometry)WhereGuv(Geometry) = Ruv [CapitalEth] (1/2)RguvAndTuv(Exotic Vacuum) = (String Tension)/zpfguv/zpf = (String Tension)^-1[(String Tension)^3/2|Vacuum Coherence|^2 [CapitalEth] 1]/zpf > 0 is negative pressure dark energy exotic vacuum that is ~ 3/4 of large-scale stuff of the Universe./zpf < 0 is positive pressure dark matter exotic vacuum that is ~ 1/4 of the large scale stuff of the Universe.Gravity effect of exotic vacuum stuff ~ c^2/zpfWhere + sign on RHS is universally repelling anti-gravity and a [CapitalEth] sign is universally attracting gravity with effective short scale coupling strengths much larger than Newtons.The key idea not found in any of Puthoffs papers on the subject of metric engineering is the local Einstein stress-energy tensor current densitys covariant divergence Tuv^;v where ;v is the Diff(4) covariant derivative relative to the metric torsion free connection field for parallel transport of tensors along tangent vector fields in curved space-time.When there is no exotic vacuum, i.e., /zpf = 0 corresponding to optimal vacuum coherence, the Bianchi identities work and we have closed current conservation of the pure geometrodynamic stress-energy tensor local currents, i.e.Tuv(Geometry)^;v = 0This prevents any practical metric engineering! In contrast, when there is exotic vacuum thenTuv(Geometry)^;v =/= 0InsteadTuv(Geometry)^;v + Tuv(Exotic Vacuum)^;v = 0Where the common string-tension factor cancels out of this current conservation equation. This essentially solves the problem for practical metric engineering bypassing the string tension problem completely! One uses the Bohm-Aharonov-Josephson effect to tweak Tuv(Exotic Vacuum) in a soft way.To be continued.The Physical Principles of Metric Engineeringby Jack Sarfatti5th draftexcerpt from the book Super CosmosThe term metric engineering was coined by Dr. Harold Puthoff. Hal, as he prefers to be called, was a US Naval Officer who then worked for the National Security Agency before going to the Stanford Research Institute where he conducted the famous Remote Viewing experiments with Russell Targ testing Uri Geller, Ingo Swann, Pat Price and other psychics in a project paid for by the CIA and Department of Defense Intelligence Agencies. I first met Hal and Russell at SRI in 1973 and that story is told in my book Destiny Matrix. Hal has held very high USG security clearances and it is well known that he is obsessed with the UFO mystery. Hal, like his co-worker Bernie Haisch, who is an editor of the Astrophysical Journal, both strongly believe in the physical reality of ?ing saucers. They, with Jacques Vallee, have been active in the NASA Breakthrough Propulsion Program and in UFO groups some financed by Laurance Rockefeller and the Howard Hughes clone Las Vegas Hotel Tycoon Robert Bigelow who owns Bigelow Aerospace Corporation. Since they take the reality of the ?ing saucers seriously so do I. The two lines of theoretical physics research that Hal has pursued for several decades now, zero point energy and a polarized vacuum model of gravity, is primarily motivated by the quest to understand how the saucers ?. The alleged reality of such advanced alien technology is clearly of immense importance to US National Security and beyond. The recent developments in physics shown in NOVAOs Elegant Universe with Brian Greene, in Stephen HawkingOs The Universe in a Nutshell, Michio KakuOs Hyperspace and Igor NovikovOs The River of Time makes time traveling alien interference in our history more probable not less probable. This is all an aspect of metric engineering defined as the practical control of space and time warps. I have discussed this in Paramount Pictures DVD Special CollectorOs Edition of Star Trek IV: The Voyage Home in Time Travel: The Art of the Possible and in Learning ChannelOs Ultra-Science: Time Travel. The ultimate form of metric engineering is seen in Q in Star Trek where a Super Mind is able to warp space-time. We also need a physics of consciousness to see if that fiction can be realized in fact. British Astronomer Royal, Sir Martin Rees who runs the laboratory where Stephen Hawking works and who is the new Master of Trinity College, Cambridge has added the dimension of Doomsday WMD to the quest for a metric engineering breakthrough in his Chapter 9 of his pessimistic Our Final Hour on the Ice Nine rip-in-space propagating at the speed of light that could literally destroy our universe. We are now at that turning point in our history where, like Mickey Mouse in Walt DisneyOs Fantasia we could, in our incompetence, destroy the entire Universe just as we are now surely destroying EarthOs Biosphere. Therefore, any aliens out there with Star Gate Time Travel and Warp Drive Super Technology are already here in order to stop us from killing them as well as ourselves. The American Christian Fundamentalist Right has a strong belief in Apocalypse Now and there is real danger that this is a self-fulfilling prophecy in a precognitive remote viewing of our future by Saint John in The BibleOs Revelations. All the more reason for me, like Paul Revere, to alert the public to these new developments in physics because only real knowledge can possibly save us and even then there is no guarantee.What does mainstream physics tell us about the possibility of metric engineering? The relevant parts of mainstream physics for metric engineering are EinsteinOs general theory of relativity and micro-quantum mechanics including the More is Different emergence of macro-quantum super?id order in ground state and vacuum instabilities developed by condensed matter Princeton physicist P.W. in the in?tionary chaotic cosmology of A. Linde consistent with the issue of Scientific American.LetOs start with EinsteinOs gravity field equation of ~ 1915. Einstein viewed pure space-time geometry like the marble in a statue by Michelangelo with gross matter and radiation as wood. EinsteinOs equation, in the 21st Century language, isSpace-Time Curvature = (Stress-Energy Density)/(String Tension)Curvature has the physical dimensions of 1/Area, String Tension has Energy/Length and Stress-Energy Density has Energy/Volume. Simple algebra confirms that this way of writing EinsteinOs equation is correct dimensionally. The String Tension is the basic parameter that Ed Witten of the Princeton Institute of Advanced Study uses in his discussions of M theory that unifies the five limiting cases of super string theory in which the elementary leptons, quarks and gauge force bosons are vibrating strings of pure energy pulsating in the extra space dimensions of Calabi-Yau hyperspace. The ordinary matter and radiation on the right hand side of EinsteinOs equation are open strings whose ends are stuck to 3Dim brane worlds of which our universe is one. You can picture a string as a tiny wormhole whose two ends need not be on the same brane world because only then can you not have equal numbers Another equivalent way to look at EinsteinOs 1915 equation from our Cosmic Justice peeking through the blindfold. That is, the stress-energy density tensor of pure marble geometry isStress-Energy Density Tensor of Pure Geometry = (String Tension)(Space-Time Curvature) (2)EinsteinOs equation is then like the static equilibrium balance of forces in architecture in which the sum of all the contributions to the stress-energy density tensor add up to a perfect zero! In this simplest of casesStress-Energy Density Tensor of Geometry + Stress-Energy Density of Matter etc. = 0 (3)All physically real objects are either tensors, spinors or twistors in the theory of relativity. This is because the coordinate map is not the physical territory. The form of the laws of physics must be the same locally no matter how the coordinate map is morphed. To this we must add the Einstein Equivalence Principle or EEP which says that even in a curved space-time, we can use the special theory of relativity locally for a special class of LIF observers to describe what is happening to a good approximation. The EEP is only meant to apply in this approximate way and it will break down if one is falling into a black hole singularity or if the microscope magnification is so large that quantum gravity zero point energy density ?ctuations in the space-time geometry itself get large. There may also be torsion fields not included in EinsteinOs 1915 geometrodynamics that may require a modification of the EEP. The spinor is a square root of a tensor and the Penrose twistor is a spinor in a complex space-time. The physics of point matrix space-time is in reality the physics of extended strings and membranes in real space-time. HawkingOs imaginary time and its connection to inverse temperature is part of that same story.The key concept for metric engineering is the Einstein current! EinsteinOs field equation is always the statement that the sum of all the stress-energy density tensors when put on the same side of the equation all balance out to exactly zero. We then take a covariant divergence of the equation to get the Einstein currents, which are conserved when added together. The covariant divergence depends on something called a connection field, which tells us how to parallel transport tensors and spinors along paths or histories in space-time and beyond including the extra dimensions of hyperspace. Every time a gauge force field is added, like a torsion field, there is an additional piece added to this connection field. EinsteinOs 1915 theory is a degenerate case of the bigger unified field theory just like a circle is a degenerate case of an ellipse. An ellipse has two centers or foci. When the two foci merge together the ellipse degenerates into a circle. EinsteinOs 1915 theory in the form of the Bianchi identities forbids practical metric engineering because it has an impenetrable barrier completely separating the marble geometric current from the wood matter current. Both kinds of currents must be able to intermingle to transform into each other in order to have soft practical metric engineering of Star Gate Time Travel traversable wormholes and weightless superluminal warp drives using the anti-gravitating exotic vacuum dark energy with negative zero point exotic vacuum pressure that is equal in magnitude, but opposite in sign, to the zero point energy density. The new Type Ia super novae data showing that our brane world Universe is accelerating in its rate of expansion, i.e. speeding up rather than slowing down. Indeed approximately 3/4 of all the stuff of our Universe on the large scale is made out of dark energy. Therefore, the idea of ancient traversable Star Gate wormholes stabilized by dark energy is not so far fetched. The brute force approach to metric engineering taken by Hal Puthoff now for at least two decades can never work because space-time is too stiff to bend directly with electromagnetic field energy density to do anything worth doing because the string tension is too large. In contrast, we can used the quantum interference of the Einstein stress-energy density currents via the Bohm-Aharonov-Josephson effect for practical metric engineering provided that the pure geometric currents are not separately conserved like they are in EinsteinOs original theory. One way to do that is to bottle or harness the dark energy as General Douglas Mac Arthur precognitively remote viewed in his Duty, Honor, Country Farewell Speech to the Cadets at West Point in 1962 in a speech made even more remarkable for its reference to the coming war in space with extra-terrestrials. Michael Turner, a professor of physics at the impossible to bottle dark energy and if EinsteinOs 1915 theory is the final theory he is correct. However, the real UFO evidence that drives Hal Puthoff like Captain Ahab after The White Wale, Moby Dick, is the evidence that suggests Professor Turner will be proved wrong in that prediction.ref.http://qedcorp.com/APS/StarGate1.movhttp:// qedcorp.com/APS/EmergentGravity.pdf === =IOm attempting to connect two 3D squares together. They are of 16points each and I?ve run them through the Bernstein equation.Now, I?m quite new to 3 dimensional mathematics and new to theBernstein formula, but its proving to be very interesting.IOve been trying for days now to get the squares to match up smoothly.There is a curvature in the surface of the one square/patch and I?mattempting to keep the same curvature through the second square (tomake half a ?t oval). IOve heard about the tangents method, abouthaving tangents from the control points on the one square to thecontrol points on the other square, which should create a smoothsurface. And here in is the problem, there is a definite line, aninward slope as the two squares/patches meet. As far I can tell thetangents line up along the join, I just donOt have a clue why the joinisnOt perfectly smooth.Many people must have run into this problem. If you have any thoughts,ideas or possible directions to pursue, they would all be very muchappreciated.T. Overton === =IOm attempting to connect two 3D squares together. They are of 16points each and I?ve run them through the Bernstein equation.Now, I?m quite new to 3 dimensional mathematics and new to theBernstein formula, but its proving to be very interesting.IOve been trying for days now to get the squares to match up smoothly.There is a curvature in the surface of the one square/patch and I?mattempting to keep the same curvature through the second square (tomake half a ?t oval). IOve heard about the tangents method, abouthaving tangents from the control points on the one square to thecontrol points on the other square, which should create a smoothsurface. And here in is the problem, there is a definite line, aninward slope as the two squares/patches meet. As far I can tell thetangents line up along the join, I just donOt have a clue why the joinisnOt perfectly smooth.Many people must have run into this problem. If you have any thoughts,ideas or possible directions to pursue, they would all be very muchappreciated.T. Overton === =I am guessing, if we take an (n_1 by n_2 by n_3 by ...n_m) m-dimensional box (where the nOs are positive integers),and we let the number of lattice points of positive integer coordinates(k_1,k_2,k_3, ...k_m), where NO common primes divide EACH k, be q(n),then:limit{n_1->oo, n_2->oo, n_3->oo, ...n_m->oo}q(n)/(n_1 * n_2 * n_3 * ...n_m) = 1/zeta(m).IE; the fraction of all finite sequences of m Ouniformly randomly chosenO positive integers, which are so that no common prime divides every integer in these sequences,is 1/zeta(m).(example of counted 4-tuple: (4,3,2,4) *is* counted because 3 is not divided by 2.)But...what is meant here by taking the limits of the nOs??I assume that each n must approach infinity OindependentlyO of the others.(Would the limit be the same if n_k was a monotonically increasing function of n_{k-1}, for example?)And, what is meant exactly by Ouniformly randomly chosenO?I am *not* quoting from a book, but rather have myself UNRIGOROUSLY derived the above well-known result today, and wish to know if the result has a more rigorous and technically-correct statement.thanks,Leroy Quet === => Because KhinchtineOs constant exists and is finite, we know that the> distribution of the integers among the terms of the simple continued> fraction of a sufficently random (whatever is meant by this) positive> real is not normal.In other words, 1 is much more likely to occur than, say, 1000 in the> continued fraction expansion of most positive reals.> So, let us say we have a real x where the geometric average of xOs> continued fraction terms approaches KhinchtineOs constant, where these> terms are {a(k)}.> So, what can be said about the number theoretical aspects of {a(k)},> such as:1) What is the likelyhood that any a(k) will be prime, as k -> oo.ie. If pcf(m) is the number of primes among a(k) for 1 <= k <= m, then> what is pcf(m) asymptotical towards?2) Same question as (1), but replace OprimesO with Osquarefree> integersO.3) What is likelihood a(k) and a(k+1) will be coprime?4) What are the expected number of divisors for all a(k) where 1 <= k> <= m?Etc etc etc ....> Of course, the number of primes among the first m CF terms of mostpositive reals would exceed that, on average, among the first mpositive integers in general, on average.Right? thanks,> Leroy> Quet === => For some even positive integer m,> we have a m-by-m grid.In this 2 player game, each player has (m^2/2) counters, > each counter numbered with a distinct integer from 1 to (m^2/2).The players take turns placing the counters into the gridOs squares in> any order the players wish.(We do not actually need the counters, for players can simply write> the numbers in the gridOs squares. But the counters make it easy to> know which numbers each player has already used, for each integer is> to be used one per player.)> (Or we can simply play this on a computer.)> Scoring: One player is rows, the other player is columns.For, say, rows, every set of adjacent integers, where each immediately> adjacent (to left/right) pair is coprime, is multiplied, then these> groups of multiplied integers are all added up to get the> row-playerOs score.For columns, we do the same, but we consider immediately adjacent> pairs which are adjacent above/below for multiplication if coprime.As to help explain what I mean, here is an example (of a game played> against myself without using any strategy):> (Who plays which number is unimportant.) 8 5 8 3> 6 1 2 6> 7 3 1 5> 2 4 7 4 Rows gets:8*5*8*3 +> 6*1*2 + 6 > + 7*3*1*5> + 2 + 4*7*4Columns gets: 8 + 6*7*2 +> 5*1*3*4 +> 8 + 2*1*7 +> 3 + 6*5*4> I would guess that higher m than 4 would be more interesting.We can use other criteria other than coprimality when determiningwhich integers to multiply.(One advantage of coprimality is that if 2 positive integers arelower, thenthey are more likely to be coprime than if they had been higher, which{I feel} improves this gameOs strategy.)Any interesting variations on this game???thanks,Leroy Quet === =Does anyone have any idea how to solve the following:x+y+z=axy+yz+xz=bxyz=cI have a hunch that x,y,z should be the roots of the cubic equations t^3-at^2+bt-c=0 === =Brian Troutwine grava .88 la saucisse et au marteau:> Does anyone have any idea how to solve the following:> x+y+z=a> xy+yz+xz=b> xyz=c> I have a hunch that x,y,z should be the roots of the cubic equations t^3-at^2+bt-c=0ThatOs true. Now youOve got many methods to solve 3rd degreeOsequations, such as Cardan or Ferrari.-- Nicolas === =Could anyone help me solve the following:Find six different nondegenerate triangles with integer sides forwhich a=16 and A=60 degrees; where the angles of the triangles arelabeled A,B,C and the sides opposite them a,b,c. === =>Could anyone help me solve the following:>Find six different nondegenerate triangles with integer sides for>which a=16 and A=60 degrees; where the angles of the triangles are>labeled A,B,C and the sides opposite them a,b,c.The law of cosines says a^2 = b^2 + c^2 - 2 b c cos(A), i.e.256 = b^2 + c^2 - b c.Sorry: the only positive integer solution is b=c=16. I think the least value of a for which there are six different triangles(if you count (a,b,c) and (a,c,b) as different when b<>c) is 49, for whichyou have the triangles[49, 16, 55], [49, 21, 56], [49, 35, 56], [49, 39, 55], [49, 49, 49], [49, 55, 16], [49, 55, 39], [49, 56, 35], [49, 56, 21]Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === =First my original post copy/pasted, then the post I am replying to byFred the Wonder Worm, before my reply below.>We have a regular hexagon whose sides are lables, clockwise from top,>A through F.>>the hexagonOs inner walls as if the walls were mirrored, but it also>affects the direction of *itself*; for whenever it crosses its own>path (as already drawn), it passes through the path, but is re?cted>as if a mirror has been placed perpendicularly to the previous pathat>the point of intersection.>know>if such a particular path actually exists, because the pathOs final>direction is heavily dependent upon the accuracy in which the path is>drawn and the accuracy of the angles re?cted.>>But I will give the order of the hexagonOs surfaces as visited by the>path (as drawn at the time of each particular crossing) below.>>(I know this, if my by-hand approximation was not too ?wed.)>>(I have no idea. You best use exact-rational arithetic to get this,if>it is possible to figure out at all.)>>E, B , D, 2 crossings, F, E, 1 crossing, F, 3 crossing, D, B, 3>crossings, F, 7 crossings, and back to its staring point.>>(If no crossings are listed between letters, than no crossings occur>between them.)>>(If someone solves this, they are going to have to post some link toa>webpage with the answer, I am afraid.)>>thanks,>Leroy Quet> If anyone wishes to check my angle chase, hereOs one description of it.> IOve tried it three times now, so either itOs right or IOm hitting a> blind spot. Start by drawing in a representative diagram up to that> point. (Make it big -- this is important!) Let the vertices in> clockwise order be labelled L, M, N, O, P, Q, so that LM is side A, MN> is side B, etc. Let the photon start at point R, and successive points> where it changes direction be S, T,..., Z. (Z is the point on the last> D-F segment, and I aim to show that Z does not actually exist.)That is, R is on side A (LM), S is on side E (PQ), T is on B (MN),> U is on D (OP), V is on ST, W is on RS, X is on F (QL), Y is on E (QS),> and Z should be on WX.Let angle LRS = theta. Then we can chase angles (all degree signs> omitted) as follows: QSR = 120 - theta> PST = 120 - theta> RST = 2*theta - 60> MTS = 120 - theta> NTU = 120 - theta> TUO = theta> PUV = theta> UVS = 120> SVW = 120> VWS = 120 - 2*theta> SWX = 120 - 2*theta> RWX = 60 + 2*theta> LXW = 180 - 3*theta> QXY = 180 - 3*theta> WXY = 6*theta - 180> XYQ = 3*theta - 120> SYZ = 3*theta - 120> XYZ = 420 - 6*thetaBut then in triangle XYZ, angles XYZ + ZXY sum to 240 degrees, which is> impossible. We conclude that the ray is actually heading at 60 degrees> _away_ from the last segment from D-F. So that ray must actually cross> segment WS rather than WX. I believe it then crosses VS and hits E> again, possibly then going via UV, TV and maybe back to the starting> point. (I think, but am not sure, that there is enough leeway for this.)So a modified version of the problem might have the pattern as A, E, B, D, 2, F, E, 2, E, 2, startGeoff.I wonder if the ray, after crossing VS does *not* then head to E,but rather heads more upwards towards UV, then (perhaps) spiralsinwardly and infinitely towards point V.But a number of other things could perhaps happen, for my diagram(hand-drawn) is ambiguous.(Around points V and Z, there are a few segments that could eachthanks,Leroy Quet === =sum[k^2/k!] from k=1 to k=infSurely there are some cute algebraic tricks to get 2e out of this, Ijust donOt know them - lil help please?thx,cdj === =>>sum[k^2/k!] from k=1 to k=inf>>Surely there are some cute algebraic tricks to get 2e out of this, I>just donOt know them - lil help please?>>thx,>>cdjWrite e^x = SUM(n=0 t =oo) (x^n/n!)Differentiate both sides and then multiply both by x Again, differentiate both sides and multiply both bu x. Put x = 1. BINGO! === => sum[k^2/k!] from k=1 to k=infThat equals sum_(k=1,oo) k/(k-1)! = sum_(k=0,oo) (k+1)/k! = d(xe^x)/dx at x = 1. === =sum[k^2/k!] from k=1 to k=infThat equals sum_(k=1,oo) k/(k-1)! = sum_(k=0,oo) (k+1)/k! = d(xe^x)/dx at x > = 1.well arenOt I just a genius now? lolthanks all,cdj === =>>sum[k^2/k!] from k=1 to k=inf> That equals sum_(k=1,oo) k/(k-1)! = sum_(k=0,oo) (k+1)/k! = d(xe^x)/dx at x > = 1.Or, in the middle,sum_(k=0,oo) (k+1)/k! = sum(k>0,k/k!) + sum(k>=0,1/k!)= sum(k>0, 1/(k-1)!) + e= 2eAs I recall, sum(k>=0, k^n/k!) is an integer multiple of e.The Bell numbers come to mind. === =cdj>> sum[k^2/k!] from k=1 to k=inf>> Surely there are some cute algebraic tricks to get 2e out of this, I> just donOt know them - lil help please?Write k^2 = k(k-1) + kand get two simpler series.LH === => sum[k^2/k!] from k=1 to k=inf>> Surely there are some cute algebraic tricks to get 2e out of this, I> just donOt know them - lil help please?e^(e^x) = 1 + e^x + e^2x/2! + e^3x/3! + ...Differentiate twice, then set x = 0. === =Here is 2 player game. (Inspired by math and other preexistingcommonly-played games.) Each player has an identical set of 15 square tiles colored asfollowed:Y = yellowR = redB = blueP = purple*Y ** *Y **** R* R* *B*Y ** *Y P* *B RB RB **PY P* PY P*** R* R* *BPY P* PY *B RB RB Players take turns making a row of tiles, one tile added at each turn.A player can ONLY add a tile if the immediately previous tile she/heis to add shares at least one color with the new tile.Each player get one point for each color-combination not among his/heropponentOs PREVIOUSLY placed pieces.(In other words, if the lines of tiles are expanding to the right andare both aligned, then a player gets a point for every piece ofhis/hers where the corresponding piece of her/his opponent is NOT tothe LEFT of the playerOs own tile in question.)And if any player cannot use all of his/her pieces (because ofcolor-matching rule), the player with the most played pieces gets 2points for each additionally played piece beyond the number played byhis/her opponent.(We could also just give each player 2 points for each played piece,since the score-difference would be the same anyway.)Sample game beginning (played without strategy here)---------------------------------------------------- Player 1 Player 2-------- ---------*Y **RB RB*Y point ** point** R*PY point *Y point** R*PY point *Y point*B *B** point P* point*B *BPY point P* pointRB **** P* pointR* RB** **RB *Betc... etc...(And the points become less frequent as play progresses.)I would suggest a greater # of colors, such as 5, 6, 7, or 8 (8 forOadvancedO play). If we have n colors, we would have (2^n -1) piecesto get all combinations of colors (except no colors).thanks,Leroy Quet === =I was looking through my files the other day and found a simple Fermatme, but thatOs not saying much since I am not an expert mathematicianso I thought I would post it here for comment by the researchcommunity.Note: I am posting this out of mere curiosity, so please be gentle :-)FermatOs Proof Below:--------------------------The is a simple proof that for the equation x^n+y^n=z^n there are nointeger solutions for n>2.BackgroundFermat must have been considering the Pythagorean Theorem x^2+y^2=z^2and observed the integer solution sets x=3I, y=4I, z=5I and mused, dointeger solutions exist for x^n+y^n=z^n (and had decided no).Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) =(x^n+y^n)^nNotice the factor (x^n+y^n) has the exponent (n-1) on the left side ofthe equation and the exponent (n) on the right side.To solve this equation we must introduce some exponent factor so thatf(scaler, n-1) and f(scaler, n) have a common denominator (n).FermatOs proof simply observes (n-1) and (n) are sequential. Theexponent operators are A^xA^y=A^(x+y) (addition) or A^x/A^y=A^(x-y)(subtraction). Sequential numbers do not have common denominatorsgreater than 1. There is no number that can be added to, orsubtracted from, sequential numbers that will change the fact thatthey are sequential.Proof-->Sequential numbers do not have common denominators greater than 1-->If two numbers are sequential, one is ODD and one is EVEN and theirdifference is 1-->Factor the numbers-ODD=ODDa*ODDbEVEN=EVENa*EVENb=EVENa*ODDb-->There are 2 equations:1=ODD-EVEN 1=EVEN-ODDReplace with factors and solve.-->1=(ODDa*ODDb)-(EVENa*ODDb) 1=(EVENa*ODDb)-(ODDa*ODDb)1=ODDb(ODDa-EVENa) 1=ODDb(EVENa-ODDa)SolveODDb=1 ODDb=1ODDa=EVENa+1 EVENa=ODDa+1Sequential numbers do not have common denominators greater than 1. === =The Fermat crackpot position is filled by James Harris and has beenfor a decade or more. YouOll have to stand in line. Thousands of professional mathematicians worked on the problem for acentury or so. And your friend waltzed in with a trivial solution??Truly amazing!>I was looking through my files the other day and found a simple Fermat>me, but thatOs not saying much since I am not an expert mathematician>so I thought I would post it here for comment by the research>community.>>Note: I am posting this out of mere curiosity, so please be gentle :-)>>FermatOs Proof Below:>-------------------------->The is a simple proof that for the equation x^n+y^n=z^n there are no>integer solutions for n>2.>>Background>Fermat must have been considering the Pythagorean Theorem x^2+y^2=z^2>and observed the integer solution sets x=3I, y=4I, z=5I and mused, do>integer solutions exist for x^n+y^n=z^n (and had decided no).>>Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) =>(x^n+y^n)^n>>Notice the factor (x^n+y^n) has the exponent (n-1) on the left side of>the equation and the exponent (n) on the right side.>>To solve this equation we must introduce some exponent factor so that>f(scaler, n-1) and f(scaler, n) have a common denominator (n).>>FermatOs proof simply observes (n-1) and (n) are sequential. The>exponent operators are A^xA^y=A^(x+y) (addition) or A^x/A^y=A^(x-y)>(subtraction). Sequential numbers do not have common denominators>greater than 1. There is no number that can be added to, or>subtracted from, sequential numbers that will change the fact that>they are sequential.>>Proof>>-->Sequential numbers do not have common denominators greater than 1>-->If two numbers are sequential, one is ODD and one is EVEN and their>difference is 1>>-->Factor the numbers->ODD=ODDa*ODDb>EVEN=EVENa*EVENb>=EVENa*ODDb>>-->There are 2 equations:>1=ODD-EVEN 1=EVEN-ODD>Replace with factors and solve.>>-->1=(ODDa*ODDb)-(EVENa*ODDb) 1=(EVENa*ODDb)-(ODDa*ODDb)>1=ODDb(ODDa-EVENa) 1=ODDb(EVENa-ODDa)>Solve>ODDb=1 ODDb=1>ODDa=EVENa+1 EVENa=ODDa+1>>Sequential numbers do not have common denominators greater than 1. === =(some snips)> Fermat must have been considering the Pythagorean Theorem x^2+y^2=z^2> and observed the integer solution sets x=3I, y=4I, z=5I and mused, do> integer solutions exist for x^n+y^n=z^n (and had decided no).Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) => (x^n+y^n)^nYou might notice that the restated equation is always true for any value of x, y, and n. Eliminating z in that way removes the dependency of the truth of the equation on the existence of a counterexample to FLT. Thus, any further proof attempt that focuses on the restated equation canOt possibly prove FLT.-- Mark Thornquist === =(some snips)Fermat must have been considering the Pythagorean Theorem x^2+y^2=z^2> and observed the integer solution sets x=3I, y=4I, z=5I and mused, do> integer solutions exist for x^n+y^n=z^n (and had decided no).Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) => (x^n+y^n)^nYou might notice that the restated equation is always true for > any value of x, y, and n. Wait a second... He then proves that this equation has no solution! This is absolutely brilliant. > Eliminating z in that way removes the > dependency of the truth of the equation on the existence of a > counterexample to FLT. Thus, any further proof attempt that > focuses on the restated equation canOt possibly prove FLT. === => To solve this equation we must introduce some exponent factor so that> f(scaler, n-1) and f(scaler, n) have a common denominator (n).Depending on what this is supposed to mean, it is either irrelevant orsatisfied by scaler[sic]^(n-1) .-- Daniel W. Johnsonpanoptes@iquest.nethttp://members.iquest.net/~panoptes /039 53 36 N / 086 11 55 W === =Unless you are a crank (which I will assume you arenot (for now)), you should avoid at all costs posting proofsof FLT. Even if you got it right, people will alljust assume youOre crazy. Statistically, itOspretty much true, and hardly any seasoned mathiewill take the time to find the ?w in your proof.If you want to learn math, and interact withmore experienced mathies, I suggest finding otherquestions to approach and try to solve - howmany polyominoes are there? Does the 3n+1sequence always terminate? If you _insist_ onstudying FLT, then it is most instructive tofind the mistakes in your proof for yourself.Believe me, unless you really suck at math(or are a crank),you truly are capable of finding your ownmistakes.Finally, and a bit hypocritically, I tried tofind the ?w in your proof but right away IcanOt tell what you mean. What is your overallform of argument? I assume it is to arriveat a contradiction -- that is, I assume that youare assuming that x^n+y^n = z^n for some fixedpositive integer triple x,y,z and fixed n>2; andthat you want to derive a contradiction from this.So why did you stop using z in your equation? Youwill have to use that z is a positive integer_somewhere_. Also, what is this functionf you introduce? What is an exponent factorand how do you plan to use it to solve theequation? Why must f(--) and f(---) havea common denominator of n? Finally, scalar isspelled scalar not scaler.Tyler> I was looking through my files the other day and found a simple Fermat> me, but thatOs not saying much since I am not an expert mathematician> so I thought I would post it here for comment by the research> community.Note: I am posting this out of mere curiosity, so please be gentle :-)FermatOs Proof Below:> --------------------------> The is a simple proof that for the equation x^n+y^n=z^n there are no> integer solutions for n>2.Background> Fermat must have been considering the Pythagorean Theorem x^2+y^2=z^2> and observed the integer solution sets x=3I, y=4I, z=5I and mused, do> integer solutions exist for x^n+y^n=z^n (and had decided no).Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) => (x^n+y^n)^nNotice the factor (x^n+y^n) has the exponent (n-1) on the left side of> the equation and the exponent (n) on the right side.To solve this equation we must introduce some exponent factor so that> f(scaler, n-1) and f(scaler, n) have a common denominator (n).FermatOs proof simply observes (n-1) and (n) are sequential. The> exponent operators are A^xA^y=A^(x+y) (addition) or A^x/A^y=A^(x-y)> (subtraction). Sequential numbers do not have common denominators> greater than 1. There is no number that can be added to, or> subtracted from, sequential numbers that will change the fact that> they are sequential.Proof-->Sequential numbers do not have common denominators greater than 1> -->If two numbers are sequential, one is ODD and one is EVEN and their> difference is 1-->Factor the numbers-> ODD=ODDa*ODDb> EVEN=EVENa*EVENb> =EVENa*ODDb-->There are 2 equations:> 1=ODD-EVEN 1=EVEN-ODD> Replace with factors and solve.-->1=(ODDa*ODDb)-(EVENa*ODDb) 1=(EVENa*ODDb)-(ODDa*ODDb)> 1=ODDb(ODDa-EVENa) 1=ODDb(EVENa-ODDa)> Solve> ODDb=1 ODDb=1> ODDa=EVENa+1 EVENa=ODDa+1Sequential numbers do not have common denominators greater than 1. === =Hash: SHA1examine the statement before posting it, and deemed it worthy ofdiscussion. With regard to whether or not it qualifies as a proof,we must first agree on a definition of the word.My understanding is that a mathematical proof is a demonstrationthat, given certain *axioms* (widely accepted truths), a presentedtheory is necessarily true. Since widely accepted is a subjectiveassessment, it often becomes necessary for a mathematician (or otherproblem solver, for that matter) to break proposed problems down intosmaller parts that are more easily reconciled with reality.If the above understanding is correct, then proving or disprovingFLT involves a demonstration of how existing axioms eithernecessitate its truth or untruth.Thus it appears that the submitted work stands upon following axioms:1) The Axiom of Variable Substitution - used here to restate theequation to:x^n(x^n+y^n)^(n-1) + y^n(x^n+y^n)^(n-1) = (x^n+y^n)^n2) In order for this equation to be solved, its writer states that(n-1) and (n)--sequential numbers--must be shown to have a commondenominator greater than 1. As a layperson, I can not confirm theaxiomatic nature of this statement, perhaps someone else can confirmor deny it.3) Sequential numbers can not share a common denominator greater than1.In short, the attempted proof reveals that the root of the problem isthat sequential numbers can not be shown to have common denominatorsgreater than 1, explaining why the equation breaks at n > 2, butworks for 1 and 2.In light of the above, there are only 3 ways to disprove this theory:1) The definition of proof as proposed is incorrect.2) One of the three (3) axioms can be shown to be false (2 lookslike a candidate from my seat, 1 & 3 appear rather obvious).3) An error in deductive reasoning was made at one of the three steps(e.g., the variable substitution was not performed correctly).With all of the brainpower in this forum, I am confident that we caneither confirm or rapidly dispense with (I agree this is more likely)this theory and perhaps emerge with a greater level of understandingas well.As iron sharpens iron,so one man sharpens another. - ProverbsiQA/ AwUBP8O79KDLMcpPQeVjEQLBpQCfXmBOKPS7Z5gwAogY332Z2P8jmkAAoMYOlI bArqOy/03cGqLxG2ljzlel=IpQk> Unless you are a crank (which I will assume you are> not (for now)), you should avoid at all costs posting proofs> of FLT. Even if you got it right, people will all> just assume youOre crazy. Statistically, itOs> pretty much true, and hardly any seasoned mathie> will take the time to find the ?w in your proof.If you want to learn math, and interact with> more experienced mathies, I suggest finding other> questions to approach and try to solve - how> many polyominoes are there? Does the 3n+1> sequence always terminate? If you _insist_ on> studying FLT, then it is most instructive to> find the mistakes in your proof for yourself.> Believe me, unless you really suck at math> (or are a crank),> you truly are capable of finding your own> mistakes.Finally, and a bit hypocritically, I tried to> find the ?w in your proof but right away I> canOt tell what you mean. What is your overall> form of argument? I assume it is to arrive> at a contradiction -- that is, I assume that you> are assuming that x^n+y^n = z^n for some fixed> positive integer triple x,y,z and fixed n>2; and> that you want to derive a contradiction from this.> So why did you stop using z in your equation? You> will have to use that z is a positive integer> _somewhere_. Also, what is this function> f you introduce? What is an exponent factor> and how do you plan to use it to solve the> equation? Why must f(--) and f(---) have> a common denominator of n? Finally, scalar is> spelled scalar not scaler.TylerI was looking through my files the other day and found a simple Fermat> me, but thatOs not saying much since I am not an expert mathematician> so I thought I would post it here for comment by the research> community.Note: I am posting this out of mere curiosity, so please be gentle :-)FermatOs Proof Below:> --------------------------> The is a simple proof that for the equation x^n+y^n=z^n there are no> integer solutions for n>2.Background> Fermat must have been considering the Pythagorean Theorem x^2+y^2=z^2> and observed the integer solution sets x=3I, y=4I, z=5I and mused, do> integer solutions exist for x^n+y^n=z^n (and had decided no).Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) => (x^n+y^n)^nNotice the factor (x^n+y^n) has the exponent (n-1) on the left side of> the equation and the exponent (n) on the right side.To solve this equation we must introduce some exponent factor so that> f(scaler, n-1) and f(scaler, n) have a common denominator (n).FermatOs proof simply observes (n-1) and (n) are sequential. The> exponent operators are A^xA^y=A^(x+y) (addition) or A^x/A^y=A^(x-y)> (subtraction). Sequential numbers do not have common denominators> greater than 1. There is no number that can be added to, or> subtracted from, sequential numbers that will change the fact that> they are sequential.Proof-->Sequential numbers do not have common denominators greater than 1> -->If two numbers are sequential, one is ODD and one is EVEN and their> difference is 1-->Factor the numbers-> ODD=ODDa*ODDb> EVEN=EVENa*EVENb> =EVENa*ODDb-->There are 2 equations:> 1=ODD-EVEN 1=EVEN-ODD> Replace with factors and solve.-->1=(ODDa*ODDb)-(EVENa*ODDb) 1=(EVENa*ODDb)-(ODDa*ODDb)> 1=ODDb(ODDa-EVENa) 1=ODDb(EVENa-ODDa)> Solve> ODDb=1 ODDb=1> ODDa=EVENa+1 EVENa=ODDa+1Sequential numbers do not have common denominators greater than 1. === => examine the statement before posting it, and deemed it worthy of> discussion. With regard to whether or not it qualifies as a proof,> we must first agree on a definition of the word.No, we already have a definition. If you wish to use the wordproof, you are well advised to use its current meaning and not makeup some new meaning. > If the above understanding is correct, then proving or disproving> FLT involves a demonstration of how existing axioms either> necessitate its truth or untruth.Yes, and the axioms in question are PeanoOs axioms, which are the verydefinition of the natural numbers. Thomas === => My understanding is that a mathematical proof is a demonstration> that, given certain *axioms* (widely accepted truths), a presented> theory is necessarily true. Since widely accepted is a subjective> assessment, it often becomes necessary for a mathematician (or other> problem solver, for that matter) to break proposed problems down into> smaller parts that are more easily reconciled with reality.Oh, and axioms are statements which are too *simple* to be proved.Example: If a = b and b = c, then a = c. Your axioms have nobusiness being claimed as axioms, although axiom 1 has the virtue ofbeing close to the relevant axioms. (You might as well add the FLTitself as axiom 4 and really shorten your proof.)You donOt get to pick out the holes in your proof and call themaxioms.-- Daniel W. Johnsonpanoptes@iquest.nethttp://members.iquest.net/~panoptes /039 53 36 N / 086 11 55 W === => Oh, and axioms are statements which are too *simple* to be proved.> Example: If a = b and b = c, then a = c. What makes that too simple to be proved? === => 1) The Axiom of Variable Substitution - used here to restate the> equation to:x^n(x^n+y^n)^(n-1) + y^n(x^n+y^n)^(n-1) = (x^n+y^n)^nYouOve restated the equation as a tautology. This is true for allconceivable values of x, y, z, and n. > 2) In order for this equation to be solved, its writer states that> (n-1) and (n)--sequential numbers--must be shown to have a common> denominator greater than 1. As a layperson, I can not confirm the> axiomatic nature of this statement, perhaps someone else can confirm> or deny it.The equation as stated above certainly does not require any particularcommon DIVISOR for (n-1) and (n). And IOm still not sure what thisalleged axiom is trying to say.Would this axiom assert that a solution for a * k^2 + b * k^2 = k^3requires a common divisor for 2 and 3?-- Daniel W. Johnsonpanoptes@iquest.nethttp://members.iquest.net/~panoptes /039 53 36 N / 086 11 55 W === = [.snip.]>My understanding is that a mathematical proof is a demonstration>that, given certain *axioms* (widely accepted truths), a presented>theory is necessarily true. No. Mathematical axioms are NOT widely accepted truths; they aremerely formal statements. Truth donOt enter into it.>2) In order for this equation to be solved, its writer states that>(n-1) and (n)--sequential numbers--must be shown to have a common>denominator greater than 1. This is nonsense as written. You mean a common DIVISOR.>As a layperson, I can not confirm the>axiomatic nature of this statement, perhaps someone else can confirm>or deny it.The statement is unsupported. The fact that n-1 and n are relativelyprime (have no common divisors other than 1 and -1) was not shown toimply FermatOs Last Theorem. DonOt know why he thinks this is the case.>3) Sequential numbers can not share a common denominator greater than>1.DIVISOR, not denominator. The OdenominatorO of an integer isusually taken to be 1, period.>In short, the attempted proof reveals that the root of the problem is>that sequential numbers can not be shown to have common denominators>greater than 1, explaining why the equation breaks at n > 2, but>works for 1 and 2.No: the attempted proof ->ASSERTS<- that FermatOs Last Theorem has ton and n-1 being relatively prime, but that assertion is notjustified. As for 1 and 2, 1 and 2 have no common divisors other than 1 and -1, so why would the assertions about n not work for n=2?>In light of the above, there are only 3 ways to disprove this theory:>>1) The definition of proof as proposed is incorrect.Your understanding of what an axiom is is certainly incorrect.>2) One of the three (3) axioms can be shown to be false (2 looks>like a candidate from my seat, 1 & 3 appear rather obvious).2 is not and was not asserted to be, an axiom. Neither is 3, for thatmatter. 3 is a conclusion derived from the basic properties of theintegers, while 2 was asserted and not proven:>> Notice the factor (x^n+y^n) has the exponent (n-1) on the left side of>> the equation and the exponent (n) on the right side.> To solve this equation we must introduce some exponent factor so that>> f(scaler, n-1) and f(scaler, n) have a common denominator (n).The last paragraph is (a) nonsense as written; what is scaler? Whatis f(scaler,n-1)? What is f(scaler, n)? What common denominator?Does he mean common factors? In short: imprenetable nonsense. === ================================================= === ===============ItOs not denial. IOm just very selective about what I accept as reality. --- Calvin (Calvin and Hobbes) === =================================================== === =============Arturo Magidinmagidin@math.berkeley.edu === =Hash: SHA1Geez...I tried to preface my post with the fact that I am NOT amathematician, I was just looking for a little peer review of an textI received from an associate. In any event:>My understanding is that a mathematical proof is a demonstration>that, given certain *axioms* (widely accepted truths), a presented>theory is necessarily true. No. Mathematical axioms are NOT widely accepted truths; they are> merely formal statements. Truth donOt enter into it.- - -snip-> Your understanding of what an axiom is is certainly incorrect.I appreciate you attempting to polish up my definition, but fail tosee how any formal statement is axiomatic? You may also want toclearthis up with both Merriam Webster (www.m-w.com) and the MITmathematics lab since they share the same definition:http://tinyurl.com/wl0m (Section 3: Axioms)All progress and greater knowledge originate from this process ofseparating the wheat from the chaff, so I do greatly appreciate theconstructive comments and illumination that others have contributedand hope that in some small way the post may have stimulated theiQA/AwUBP8QWvaDLMcpPQeVjEQI9sQCgvlW+ v5MIEIMXmn8Xk0mnz6rEiL0AoMYqU53LXg0i2RFQ+cICbmaO/2h8=Nc/3 === = > Finally, and a bit hypocritically, I tried to> find the ?w in your proof but right away I> canOt tell what you mean.He seems to be tacitly assuming that if m and n are coprime, so are k^mand k^n. (And the second half of the proof simply establishes thatn-1 and n are coprime.)-- Daniel W. Johnsonpanoptes@iquest.nethttp://members.iquest.net/~panoptes /039 53 36 N / 086 11 55 W === => Unless you are a crank (which I will assume you are> not (for now)), you should avoid at all costs posting proofs> of FLT. Even if you got it right, people will all> just assume youOre crazy.I have never assumed anyone is crazy for posting a FLT proof;just optimistic. And if it even is right, all the better.> Statistically, itOs> pretty much true, and hardly any seasoned mathie> will take the time to find the ?w in your proof.ThatOs strange - every single FLT proof I have seen here overthe years has been shot down by someone fairly quickly.(...)---J K Hauglandhttp://www.neutreeko.com === => I was looking through my files the other day and found a simple Fermat> me, but thatOs not saying much since I am not an expert mathematician> so I thought I would post it here for comment by the research> community.With many simple proofs of hard theorems, there is a very simple way to see that is something fishy, and it works with this proof as well. It is well known that a^n + b^n = c^n has plenty of solutions in positive integers a, b, c if n = 2 and none have ever been found if n > 2. So whatever proof you have that a^n + b^n = c^n _must_ fail if n = 2. If it doesnOt fail for n = 2 then it proves something wrong, so even if you donOt understand the proof you _know_ it cannot be correct. The proof you posted never requires that n > 2. === => The proof you posted never requires that n > 2.It never even requires that n > 1.-- Daniel W. Johnsonpanoptes@iquest.nethttp://members.iquest.net/~panoptes /039 53 36 N / 086 11 55 W === => With many simple proofs of hard theorems, there is a very simple way > to see that is something fishy, and it works with this proof as well. > (SNIP)The proof you posted never requires that n > 2.Care should be taken, though. The proof of the irrationality ortranscendance of pi requires that pi be the ratio of a circleOscircumference to itOs diameter in a rather subtle, not-obvious way. === =fuffy> I was looking through my files the other day and found a simple Fermat> me, but thatOs not saying much since I am not an expert mathematician> so I thought I would post it here for comment by the research> community.>> Note: I am posting this out of mere curiosity, so please be gentle :-)>> FermatOs Proof Below:> --------------------------> The is a simple proof that for the equation x^n+y^n=z^n there are no> integer solutions for n>2.>> Background> Fermat must have been considering the Pythagorean Theorem x^2+y^2=z^2> and observed the integer solution sets x=3I, y=4I, z=5I and mused, do> integer solutions exist for x^n+y^n=z^n (and had decided no).>> Restate the equation: x^n (x^n+y^n)^(n-1) + y^n (x^n+y^n)^(n-1) => (x^n+y^n)^n>> Notice the factor (x^n+y^n) has the exponent (n-1) on the left side of> the equation and the exponent (n) on the right side.>> To solve this equation we must introduce some exponent factor so that> f(scaler, n-1) and f(scaler, n) have a common denominator (n).>> FermatOs proof simply observes (n-1) and (n) are sequential. The> exponent operators are A^xA^y=A^(x+y) (addition) or A^x/A^y=A^(x-y)> (subtraction). Sequential numbers do not have common denominators> greater than 1. There is no number that can be added to, or> subtracted from, sequential numbers that will change the fact that> they are sequential.>> Proof>> -->Sequential numbers do not have common denominators greater than 1> -->If two numbers are sequential, one is ODD and one is EVEN and their> difference is 1>> -->Factor the numbers-> ODD=ODDa*ODDb> EVEN=EVENa*EVENb> =EVENa*ODDb>> -->There are 2 equations:> 1=ODD-EVEN 1=EVEN-ODD> Replace with factors and solve.>> -->1=(ODDa*ODDb)-(EVENa*ODDb) 1=(EVENa*ODDb)-(ODDa*ODDb)> 1=ODDb(ODDa-EVENa) 1=ODDb(EVENa-ODDa)> Solve> ODDb=1 ODDb=1> ODDa=EVENa+1 EVENa=ODDa+1>> Sequential numbers do not have common denominators greater than 1. === =>> fuffy> fuffy>> >> Fuffy has refined its tactics. First, all that Fuffy did was>> to keep the name of the most current poster in a thread>> from appearing on Google.> Free clue for the clueless: If you want to see the>> threads have lots of sub-threads, and the default>> order makes it difficult to find recent comments>> in more than one.> What is to be done about Fuffy?> Duh-h-h. DonOt ask me.> Well, I suspect virtually every Google user but you>> already knew about sort by date and how to find >> recent posters.> IOm a Mathie.> People want to know who the last poster in a thread is,>without having to do a Google Advanced Search. Second clue for the clueless:Sort by date is on every thread with more than one message. Lookaround. Nothing to do with Advanced Search.> For>example, if Google shows Justin Van Twinkie as the last>poster, I wonOt bother to read the last postingThen youOll have no idea whether or not 15 people have posted sincethe last time you read the thread. === =>> fuffy> fuffy> Fuffy has refined its tactics. First, all that Fuffy did was>> to keep the name of the most current poster in a thread>> from appearing on Google.> Free clue for the clueless: If you want to see the>> threads have lots of sub-threads, and the default>> order makes it difficult to find recent comments>> in more than one.> What is to be done about Fuffy?> Duh-h-h. DonOt ask me.> Well, I suspect virtually every Google user but you>> already knew about sort by date and how to find >> recent posters.> IOm a Mathie.> People want to know who the last poster in a thread is,>without having to do a Google Advanced Search. Second clue for the clueless:Sort by date is on every thread with more than one message. Look> around. Nothing to do with Advanced Search.For>example, if Google shows Justin Van Twinkie as the last>poster, I wonOt bother to read the last postingThen youOll have no idea whether or not 15 people have posted since> the last time you read the thread.All right, now I see what you mean. Now I know how to keep McCallum from wasting my time. On the otherhand, IOll bet there are Google Users other than myself who donOtyou seem to want to believe, and for people who donOt know how itworks, McCallum fucks things up in a way that he has no right to. === =Suppose you have some random variables X_j that satisfythe conditions of the central limit theorem (identialmeans and variances). We all know that the SUM of suchrandom variables tends toward a Gaussian distribution.Now suppose that you have some function f(X) that maps each of these random variables X_j. Suppose for simplicitythat the function f(X) is invertible, at least in some restricteddomain, but perhaps nonlinear.Is there any statement that can be made about the distributionof the sum of f(X_j)?References would be greatly appreciated, also.Much thanks,JB === =>Suppose you have some random variables X_j that satisfy>the conditions of the central limit theorem (idential>means and variances). We all know that the SUM of such>random variables tends toward a Gaussian distribution.>Now suppose that you have some function f(X) that maps >each of these random variables X_j. Suppose for simplicity>that the function f(X) is invertible, at least in some restricted>domain, but perhaps nonlinear.>Is there any statement that can be made about the distribution>of the sum of f(X_j)?Well, obviously you want the f(X_j) to satisfy conditionson means and variances. They donOt have to be identical, though. LindebergOs Theorem says if Y_j are independent with means mu_jand variances sigma_j^2, M_n = sum_{j=1}^n mu_j and S_n^2 = sum_{j=1}^n sigma_j^2, with 1/S_n^2 sum_{j=1}^n E[(Y_j - mu_j)^2 I(|Y_j - mu_j| >= S_n epsilon) -> 0as n -> infinity for all epsilon > 0 (I(A) being the indicator function of A, i.e. 1 if A is true and 0 otherwise), then 1/S_n sum_{j=1}^n (Y_j - mu_j) converges in distribution to a standard normal random variable.A condition that may be easier to apply is that 1/S_n^3 sum_{j=1}^n E |(Y_j - mu_j)^3| -> 0 as n -> infinity.Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === =>Suppose you have some random variables X_j that satisfy>the conditions of the central limit theorem (idential>means and variances). We all know that the SUM of such>random variables tends toward a Gaussian distribution.Actually we donOt know that: assuming your X_j are independent, but not identically distributed, identical means and variancesare not enough for a Central Limit Theorem: you need the Lindebergcondition. An amusing example isX_j = 0 with probability 1-1/j^2 +/- j with probability 1/(2 j^2) eachso all X_j have mean 0 and variance 1. But since sum_j 1/j^2 < infinity,with probability 1 all but finitely many X_j are 0, and thus 1/n sum_{j=1}^n X_j -> 0 almost surely. >Now suppose that you have some function f(X) that maps >each of these random variables X_j. Suppose for simplicity>that the function f(X) is invertible, at least in some restricted>domain, but perhaps nonlinear.>Is there any statement that can be made about the distribution>of the sum of f(X_j)?Well, obviously you want the f(X_j) to satisfy conditions> on means and variances. They donOt have to be identical, though. > LindebergOs Theorem says if Y_j are independent with means mu_j> and variances sigma_j^2, M_n = sum_{j=1}^n mu_j and > S_n^2 = sum_{j=1}^n sigma_j^2, with > 1/S_n^2 sum_{j=1}^n E[(Y_j - mu_j)^2 I(|Y_j - mu_j| >= S_n epsilon) -> 0I left out a bracket: that should be 1/S_n^2 sum_{j=1}^n E[(Y_j - mu_j)^2 I(|Y_j - mu_j| >= S_n epsilon)] -> 0> as n -> infinity for all epsilon > 0 (I(A) being the indicator function of > A, i.e. 1 if A is true and 0 otherwise), then > 1/S_n sum_{j=1}^n (Y_j - mu_j) converges in distribution to a standard > normal random variable.E.g. suppose for simplicity all X_j and f(X_j) have mean 0, f(0) = 0, and there are positive constants a and b such that a(y-x) < f(y) - f(x) < b(y-x) whenever x < y. Thena^2 Var(X_j) <= Var(f(X_j)) <= b^2 Var(X_j). IOll write S_n^2 = sum_{j=1}^n Var(X_j) and SO_n^2 = sum_{j=1}^n Var(f(X_j)),so a S_n <= SO_n <= b S_n.In LindebergOs conditionf(X_j)^2 I(|f(X_j)| > SO_n epsilon) <= b^2 X_j^2 I(|X_j| > S_n epsilon a/b)so if X_j satisfy the condition, so do f(X_j). Robert Israel israel@math.ubc.caDepartment of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 === =OK I see where I went wrong now, I think. Let me try again.Consider the Category, (I use capital C to indicate it may have the cardinality of all classes, thus have to be a super-category or whatever);whose objects are all ordinary categories, and whose arrows are functors.This Category has natural transformations defined within it, which are(I think?) mappings from functors to functors. So they are a sort of2nd-order Arrow in this Category.So, given their properties, what do Natural Transformations (in this Category) correspond to in the way of mappings-of-arrows in an ordinary category?Does this make sense now? What special named sort of arrow-transformation do they correspond to?---------------------------------------------------------- -------------------- Bill Taylor W.Taylor@math.canterbury.ac.nz------------------------------- ----------------------------------------------- I shot an arrow in the air And down it came, I know not where. I looked for it up in a tree Which was, though, just a categOry!---------------------------------------------------- -------------------------- === =>A and B have different dimensions,>but AB and BA are both square.>Can anyone provide a proof showing the eigenvalues are the same for AB and BA ?Side question: WhatOs your favorite linear algebra text for answeringthis sort of question? I pulled out my Horn and Johnson but realized Ihad no idea where to look to find a proof, if there is one.Eigenvalue was too broad an index entry.Related question: Do you have a favorite book coveringspecially-structured matrices? That would include, for example, fastToeplitz inversion methods? Or could easily answer the question whensomebody asks, is there a name for this kind of matrix? - Randy === =0072>> IOve got a list of points (in x,y form) that are the corners of a> polygon, in order. ItOs not necessarily a convex polygon. Is there a> standard algorithm for determining whether a given point is inside> or outside the polygon? All this takes place in the plane... For> practical purposes, an algorithm is ok if it can handle up to 7 points> decently.>> Many thanks -Adrian> This is probably in the faq at comp.programming.games.algorithms, or> something like that. Google will probably also help.>> I know itOs in the comp.graphics.algorithms FAQ.>> http://www.faqs.org/faqs/graphics/algorithms-faq/>> Check out question 2.03.>> - Randy === =>> I have looking at a few web pages dealing with the largest known> calculated primes and a great deal of computational time is taking> into searching for these numbers and verifying they are primes. I have> seen the EuclidOs proof of infinitude primes and it occurs that me> that super-large prime numbers can be calculated using the following:>> Others have already given you an example of why your idea wonOt ?, butIthere> is no largest prime (and therefore an infinite number of primes) is as> follows:>> If there is a largest prime, P, then the number of primes is finite. Wecan> therefore form a new number, N, which is one greater than the product of> all primes. Therefore, N > P (and, indeed, it would be very much greater> than P).>> When divided by any prime in our list, it leaves remainder 1. Therefore,> /either/ it is prime /or/ it is the product of two or more primes, atleast> one of which is greater than P.>> In /either/ case, P has been shown not to be the largest prime number.>> Nope. Nowhere have you assumed that the list of primes known is> complete up to P. YouOve simply proved that the finite list of> known primes is not the list of all primes.>> If you use EuclidOs proof as constructive, then the sets you generate0079> {2,3,7}> {2,3,7,43}> {2,3,7,13,43,139}> {2,3,7,13,43,139,3263443}> and thence you find the new primes {547,607,1033,31051}, all of which> are less than the currently largest known prime 3263443.>> DonOt forget the second case! :-)>> DonOt forget that if youOre pretending that you donOt know what> the primes are, you canOt suddenly pull otherwise well-known> features of the prime numbers out of a hat.>> Phil> --> Unpatched IE vulnerability: ADODB.Stream local file writing> Description: Planting arbitrary files on the local file system> Exploit: http://ip3e83566f.speed.planet.nl/eeye.html> (but unrelated to the EEye exploit) === =>Well duh!>All of _what_, though.Primes.John === => Nope. That is prior art. However taxing folks on their exusions and > bodily productions is not far in the future. The jism tax. > ItOs the coming thing.HOWWWWWWWWWWLL !!!!!! Pun of the week!But seriously, we already have, here in NZ, proposed taxes on emissions,not of people but cows. In order to comply with the perceived obligationsunder the Kyoto protocol, (hey thereOs a song line there... Kyo-to pro-to..),our PC government proposed a new cattle emission tax on farmers for the allegedharm to the ozone layer due to emitted methane!Naturally, this was immediately dubbed the fart tax by the predatory media,and attracted so much derision, joking, and protest from the farming communitythat itOs unlikely to see the light of day; which is in some ways a pitybecause a fart tax would have been a wondrous thing! (Even if smellinga little fishy!)------------------------------------------------------- ----------------------- Bill Taylor W.Taylor@math.canterbury.ac.nz------------------------------- ----------------------------------------------- Camou?ge condoms: So they wonOt see you coming.------------------------------------------------------ ------------------------ === =>I should note that the above carries no attribution. It is>>copyrighted material originally published in The Onion,>>but I couldnOt locate any of the original Onion material>>online anywhere. >>IOve already posted the Onion material (actually, IOve posted the link>to the material fron the OnionOs own website) elsewhere in this thread.Huh. I didnOt realize their archive went back that far. I once triedand eventually gave up. ItOs the one with several eminent physicistsdiscussing Big Bang theory. Like man, what if the whole universe is,like, a big Atom in another Universe? Wow, heavy, man. That sort ofthing. - Randy === =When a Riemann surface is constructed by joining copies of the cutplane the arbitrariness in the choice of cuts carries over into anarbitrariness in the Riemann surface. And where there is no uniquedomain there is no unique function so it is incorrect to speak ofthe function w(z) defined by an initially given relation f(w,z)=0.It is rigor not pedantry to remark that the derivable functions aremany and that the initially given relation is just what they have incommon. When Riemann introduced his Riemann surfaces it may be that he didso to eliminate the multiplicity that comes with branches. But themultiplicity reappears in this altered form. To understand it one hasto stay with analysis and not move on to a more abstract geometricaltreatment. For other notes on this topic visit my websitewww.riemannsurfaces.info. === =>When a Riemann surface is constructed by joining copies of the cut>plane the arbitrariness in the choice of cuts carries over into an>arbitrariness in the Riemann surface.Lucky that thatOs not the only way to construct a Riemann surfacethen...> And where there is no unique>domain there is no unique function so it is incorrect to speak of>the function w(z) defined by an initially given relation f(w,z)=0.Look up analytic continuation in an advanced book on complexanalysis: the standard construction of _the_ Riemann surface heredoes not have anything to do with cuts, and thereOs nothingarbitrary about it. The surface is just the set of all functionelements which can be reached by continuation along a path, startingwith a given function element.>It is rigor not pedantry to remark that the derivable functions are>many and that the initially given relation is just what they have in>common.> When Riemann introduced his Riemann surfaces it may be that he did>so to eliminate the multiplicity that comes with branches. But the>multiplicity reappears in this altered form. To understand it one has>to stay with analysis and not move on to a more abstract geometrical>treatment.> For other notes on this topic visit my website>www.riemannsurfaces.info.> David C. Ullrich === =>Message-id: <2410d7e.0311241320.5b02c68e@posting.google.com>Can someone provide with a mathematical algorithm which explains the>horrendous pixel-crime perpetred by the infamous Mr. Mensanator?>>http://www.thequantummachine.com/images.phpHey, the new image is a big improvement over the original. A littleconstructive criticism helps doesnOt it?>>I thought that my TFT screen had been degraded by some air pollutant,>but then I realized that it was only his image which had some fungus>on it... :-)--MensanatorAce of Clubs === =>> Given an integral domain R, can we not construct a field in the same >> way we construct Q from Z? I.e., equivalence classes on R x >> (R{0}), where (a, b) ~ (c, d) iff a d = b c . (Integral domains >> are by definition commutative, no? So says Herstein.)>>If R has a 1, then the mapping f(r) = (r,1) gives the desired>embedding; but without the 1, how do we embed R?You are not really mapping to (r,1), you are mapping to the class of> (r,1). So map r to the class of (r^2,r) if r is nonzero, and map 0 to> the class of (0,r) for arbitrary r different from 0. > Doh! Of course; because cancellation holds in R (follows fromintegrality), if we map r,s to (r^2,r) and (s^2,s), resp., then r^2.s= s^2.r iff r = s...> === ========================================================== === ======> ItOs not denial. IOm just very selective about> what I accept as reality.> --- Calvin (Calvin and Hobbes)> === ========================================================== === ======Arturo Magidin> magidin@math.berkeley.edu====Please help with equations/sketches for a circular torus intersectionwhen the cutting plane is not parallel to its axis of symmetry.Equations may be expressed in terms of torus tube radius, tubedisplacement from axis,inclination/length of perpendicular from torusaxis/center to the intersecting plane. References requested preferablyfrom the internet. TIA === => Please help with equations/sketches for a circular torus intersection> when the cutting plane is not parallel to its axis of symmetry.> Equations may be expressed in terms of torus tube radius, tube> displacement from axis,inclination/length of perpendicular from torus> axis/center to the intersecting plane. References requested preferably> from the internet. TIAjust take a three-dimensional parametrisation of the torus like ( cos s * (cos t + 2) )f(s,t) = ( sin s * (cos t + 2) ) ( sin t )This is for a torus of displacement 2 and tube radius one. With vectorcalculus you now can easily deduce the cutting with any plane.Rene.-- Ren.8e MeyerStudent of Physics & MathematicsZhejiang University, Hangzhou, China === =An interesting integral just appeared in alt.math, and there should bea neater solution than I found. The problem is to evaluate int_0^1 int_0^{1-x} 1/(1-axy) dy dx,where |a| < 4.My solution was to expand into a geometric series (justified since |a|< 4, 0 <= y <= 1-x ==> |4axy| < 1), obtaining int_0^1 a^n x^n (1-x)^(n+1) dx,and then use the standard identity int_0^1 x^a (1-x)^b = Gamma[a+1] Gamma[b+1]/Gamma[a+b+2].This yields the integral as a power series, sum_{n=0}^infty a^n n!^2/(2n+2)!,which is then recognizable as 2 arcsin(sqrt(a)/2)^2 --------------------- . aBut there ought to be a direct way to see this. Any takers?--Ron Bruck === =Two minor corrections: that should read |a|<4, 0 <= y <= 1-x ==> |axy| < 1,and we obtain for the value of the integral (1-x)^(n+1) sum_{n=0}^infty int_0^1 a^n x^n ----------- dx. n+1But the final answer remains unchanged.--Ron Bruck> An interesting integral just appeared in alt.math, and there should be> a neater solution than I found. The problem is to evaluate int_0^1 int_0^{1-x} 1/(1-axy) dy dx,where |a| < 4.My solution was to expand into a geometric series (justified since |a|> < 4, 0 <= y <= 1-x ==> |4axy| < 1), obtaining int_0^1 a^n x^n (1-x)^(n+1) dx,and then use the standard identity int_0^1 x^a (1-x)^b = Gamma[a+1] Gamma[b+1]/Gamma[a+b+2].This yields the integral as a power series, sum_{n=0}^infty a^n n!^2/(2n+2)!,which is then recognizable as 2 arcsin(sqrt(a)/2)^2> --------------------- .> aBut there ought to be a direct way to see this. Any takers?--Ron Bruck === =Set R_1 = x+y, R_2 = xyIs there an easy way of writing the polynomial x^n + y^n in terms ofR_1 and R_2? I know it can be done by expanding out with R_1^n, butthis is obviously not practical for large n. Is there some sort ofidentity that allows you to write the answer down immediately,similar to the binomial theorem? === => Set R_1 = x+y, R_2 = xyIs there an easy way of writing the polynomial x^n + y^n in terms of> R_1 and R_2? I know it can be done by expanding out with R_1^n, but> this is obviously not practical for large n. Is there some sort of> identity that allows you to write the answer down immediately,> similar to the binomial theorem?The buzzword is Dickson polynomial.Ley u = x + y and x = xy. Form the generating functionF(t) = sum_{n=0}^infinity (x^n + y^n)t^n.ThenF(t) = 1/(1-xt) + (1-yt) = (2 - ut)/(1 - ut + vt^2) = (2 - ut)sum_{m=0}^infinity (u + vt)^m t^m = (2 - ut)sum_{n=0}^infinity t^n sum_m {m choose n-m}u^{2m-n} v^{n-m}etc. Pulling out the coefficient of t^n gives D_n(u,v)the Dickson polynomial of the first kind with D_n(u,v) = x^n + y^n.-- Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.htmlNeedless to say, I had the last laugh. Alan Partridge, _Bouncing Back_ (14 times) === => Set R_1 = x+y, R_2 = xy>> Is there an easy way of writing the polynomial x^n + y^n in terms of> R_1 and R_2? I know it can be done by expanding out with R_1^n, but> this is obviously not practical for large n. Is there some sort of> identity that allows you to write the answer down immediately,> similar to the binomial theorem?HereOs my attempt:Write f_n = x^n+y^n. Then expand (x+y)*(x^n+y^n) to get the recurrencerelation:f_(n+1) - R_1 * f_n + R_2 * f_(n-1) = 0with the initial conditions: f_0 = 2 and f_1 = R_1.The solution to the recurrence relation may be written as:f_n = A * u^n + B * v^n, whereu and v are roots of the quadratic equation t^2 - R_1 * t + R_2 = 0.The coefficients A and B may be found by considering the initial conditions.-Michael. === =Set R_1 = x+y, R_2 = xy> HereOs my attempt:Write f_n = x^n+y^n. Then expand (x+y)*(x^n+y^n) to get the recurrence> relation:> f_(n+1) - R_1 * f_n + R_2 * f_(n-1) = 0> with the initial conditions: f_0 = 2 and f_1 = R_1.That is a special case of the NewtonOs identities. > The solution to the recurrence relation may be written as:> f_n = A * u^n + B * v^n, where> u and v are roots of the quadratic equation t^2 - R_1 * t + R_2 = 0.DonOt you think that the solutions to this equation would be x and y.... > The coefficients A and B may be found by considering the initial conditions.... with A=1 and B=1? So this approach wonOt give much information, as thesolution you get will be (drums, please)f_n=x^n+y^n :)Jyrki === =>> Set R_1 = x+y, R_2 = xy>> HereOs my attempt:>> Write f_n = x^n+y^n. Then expand (x+y)*(x^n+y^n) to get the recurrence> relation:> f_(n+1) - R_1 * f_n + R_2 * f_(n-1) = 0> with the initial conditions: f_0 = 2 and f_1 = R_1.>> That is a special case of the NewtonOs identities.>> The solution to the recurrence relation may be written as:> f_n = A * u^n + B * v^n, where> u and v are roots of the quadratic equation t^2 - R_1 * t + R_2 = 0.>> DonOt you think that the solutions to this equation would be x and y....Indeed....>> The coefficients A and B may be found by considering the initialconditions.>> ... with A=1 and B=1? So this approach wonOt give much information, as the> solution you get will be (drums, please)>> f_n=x^n+y^n :)Oh well, it seemed like such a good idea at the time.... :-)-Michael. === =Set R_1 = x+y, R_2 = xyIs there an easy way of writing the polynomial x^n + y^n in terms of> R_1 and R_2? I know it can be done by expanding out with R_1^n, but> this is obviously not practical for large n. Is there some sort of> identity that allows you to write the answer down immediately,> similar to the binomial theorem?Search for NewtonOs identities (a useful recurrence relation) andWaringOs formula. They are also helpful for a larger number of variables(x,y,z,etc.). I donOt know what would be the simplest formula for twovariables. WouldnOt any formula for DicksonOs polynomials do? Searchfor any of these key phrases!Jyrki Lahtonen, Turku, Finland === => Ok, I apologize.I did not say it was fraud, I _asked_ if it was.You say it was not, that answers the question.Ok. I accept your apologies. I am little tired of this controversy,and seems stupid to get angry with people I donOt personally meet.> ItOs just that extraordinary claims require extraordinary evidence. What you > present on your web site cannot even be considered evidence, let alone> extraordinary evidence. IOm supposed to take your word that if presented> correctly, the lines would be parallel? ThatOs not how science is done.I agree with that. As I said, the main investigation was done byCrater&McDaniel. I didnOt reproduce step by step, but made my owncalculations and simulations that were consistent. At that time thecomputer simulation was very cost, so I made some simulations thatshowed the same level that theirs.Also, revised the protocol, and the pattern can be fitted with thatmean deviation inside of the mounds, the problem is trying to do byhand. But it is easy, just using least squares (if you insist, asCrater, in a coordinate fit).I will prepare when I get some time to do it by computer, you mustnotice that at the time I did the diagram, as it is rotated, it wouldhave took me a considerable time to locate the correspondingcoordinates and there was the issue of the non-rectified image.What I have thought is to use a superimposed image, with the centersclearly marked, so it is visually discernible how far is the deviationin each mound.> And letOs not forget that you solicited comments. Do you think that I am the> only one who sees problems with what you presented? You should be happy to > see such comments so that you can correct the situation. The problem is that the critics here and other posts were far fromgentle. I am not accustomized to this. Also notice that I am littletired of writing some statements, and getting them ignored.For example, I stated that the simulations (and calculation by handusing area ratios will do) show that you need about 75 or more moundsto get reasonable levels of that pattern being by chance.And a poster in my forum came with 106 dots and showed some nicealignments. Perhaps I loose patience very fast, but I had to explainthat not only those nice alignments were present, but very likely themounds pattern. Other thing was to extract it, which would likelyrequire a computer.> I will clarify also in my webpage soon, Good.givin links to your webpage.DonOt you have your priorities wrong? ShouldnOt you focus on what _you_ are> presenting? It is now closed. I think the best test would be to perfom a completescan of the martian surface. It could be used to detect crater chainsand make crater population counts also (they are similar to mounds,but with lightning inverted). However, in order to avoid bias, Ishould make it independent from the mounds, and when I detectautomatically, this may be somehow indicative of non-randomness.> You will be acussed of dishonesty. Dishonesty? I just presented what I saw. You admit that the original image> was not orthorectified, so I was honest in saying that the lines do not appear> parallel. Now if I made a mistake, it was an honest one, because I used the> image that _you_ provided. Rather than explaining in the text why the image> was incorrect, wouldnOt it have been better to post a correct image?But that was said in the webpage. I retire the accusation ofdishonesty here and in my webpage, accepting that you did not notice.And yes, I will do that. I will also publish the source code I use andthe link to the original image in NSSDC website.> You can sue me also, if you want. I am wishing it.Sue you for what? Calling me dishonest? Calling me pathetic? Calling me a slow> thinker? Calling me stupid? These comments wonOt make you look good.I retire those comments, but you must notice that I have heardeverything, from being a pseudoscientist, to not knowing probabilitynotions, fraud, and countless others.The problem is a mathematical one. For example my claim that this isthe only pattern (after a square-based one) with the greater number ofDIFFERENT parallel/perpendicular directions for 5 points (BAGED, plusrepeating P) goes unchallenged. And this is what irritates me. Thatclaim is just a very defined one, testable with analitical geometry.But based on a diagram, so... could I have missed some configuration?I recommend to read most of the material I present, at leastsuperficially, before making comments, and let the childish I am moreintelligent than you issues out of the conversation. === =>Message-id: <2410d7e.0311220235.6c366ff9@posting.google.com> You are one of those who confuse the probability of an event occuring> with the event itself. Duh...It is you who confuse it. You still believe that the probability ofthat event has turned to 1. This is a claim I have heard countlesstimes. Yet a math PhD laughed at it.see how they do that.Also the crater chains are analysed probabilistic, but still they arethere since some million years ago... > In the mounds problem, the probabilistic experiment is having 6 mounds> formed by some process. The process has a great number of pausible> outcomes, depending on its particular physical nature. If you assume> some type of a random formation process, then the probability of> getting the formation shown is extremely low.Instead of wasting your time uploading gifs and accusing people, why> donOt you program a simulation of 6 mounds forming at random, set your> accuracy range for parallel and perpendicular lines and see of you can> get that or similar formations and what the frequency of those are.> That will convince you the probability of getting that formation or> similar ones is extremely low. ThatOs all there is to it.I have done that particular experiment. I used parallel lines only fora computer simulation of a number of points, not just 6 but greater.Still, for such a number of parallel relationships I got 1/1000 for 6points. I draw some of them at hand (I got numbers in the screen onlybecause at that time I didnOt get any notion of image processing).Most were unremarkably, and there was a tendency to form what I calleddegenerated lines (a bug).You can do by yourself and check. Otherwise you are talking withoutfoundation, just as counting sheeps, and you know. DO THE SIMULATIONAND WHEN YOU HAVE A FIGURE, WE TALK AGAIN. If not, you are makingpseudoscience. === =>Message-id: <1f366ae.0311240955.b79503f@posting.google.com>>Message-id: <2410d7e.0311220235.6c366ff9@posting.google.com>[snip]> >> You just canOt _prove_ itOs not random. Probability has no meaning>> for something that has already happened. You claim the odds are>> 200,000,000,000 to 1 and then you say that no other configuration>> has this property.> Duh.>> >>[snip]>>You are one of those who confuse the probability of an event occuring>with the event itself. Duh...>>In the mounds problem, the probabilistic experiment is having 6 mounds>formed by some process. The process has a great number of pausible>outcomes, depending on its particular physical nature. If you assume>some type of a random formation process, then the probability of>getting the formation shown is extremely low.The formation? DonOt you mean a formation?>>Instead of wasting your time uploading gifs and accusing people, why>donOt you Why doesnOt the OP have a mathematically correct drawing on his web site?>program a simulation of 6 mounds forming at random, What, exactly, is the geological process I am supposed to simulate? Or should Ijust sprinkle random pixels onto an image?>set your accuracy rangeAccuract range? This is math, not physics. There is no range allowed indetermining parallel and perpendicular.>for parallel and perpendicular lines and see of you can>get that or similar formations and what the frequency of those are.>That will convince you the probability of getting that formation or>similar ones is extremely low. ThatOs all there is to it.YouOre wrong. There is a world of difference between that formation andsimilar formations.>>By the way, has you ever been to a casino? Have you ever looked at the night sky and noticed all the polygons formed bythe stars?Do you think there is some mysterious reason for this?>The number you see the>roullette ball sitting on of course just happended but you canOt bet>on it. Have you thought about _why_ they wonOt let you bet on it? Do you know what theprobability is of an event that has already happened? >If you think talking about its probability has no meaning>because it just happened, Whatever the probability was before the event, after the event the probabilityis simply 1.Possibly you didnOt see this example, so IOll repeat it:Put 64 coins in a box and shake. Note the pattern of heads and tails. Theprobability of that pattern occuring is1/18446744073709551616and yet it happened! Shake the box again. The pattern you see now also had a1/18446744073709551616chance of occuing and it happened also. The chance of BOTH those patternsoccuring back to back is1/340282366920938463463374607431768211456What conclusion do you draw from this?>then if you have just won, why should they>pay you back 36 times your bet? They shouldnOt, roullette payouts are 35 to 1. Of course, you would know thisif youOve ever been to a casino.>Just take your money back and thatOs>it.:)--MensanatorAce of Clubs === => Whatever the probability was before the event, after the event the probability> is simply 1.The probability is related to the chances of that event happening. Iwould not apply to events that have already happened. The p value doesnot get altered, because p is predictive, and you are talking of avalue which is not predictive.I would think that it is more a semantic question.I would assign 0 to event which are impossible and 1 to event that aresurely TO HAPPEN (in the future). === =>Message-id: <2410d7e.0311250420.2e0c3caf@posting.google.com>> Whatever the probability was before the event, after the event the>probability>> is simply 1.>>The probability is related to the chances of that event happening. I>would not apply to events that have already happened. The p value does>not get altered, because p is predictive, and you are talking of a>value which is not predictive.>>I would think that it is