JSH: NSA is listening to you
	JSH has been threatening for several years to release his factoring algorithms to "third parties" that will cause complete financial collapse. Well, the Financial collapse happened. JSH continues to threaten the world with his math, a technical terrorist. NSA is investigating with great vigor all possibilities and has had JSH in... more » By harry  - 2:27am - 2 new of 2 messages

	Game: Labyrinthine Loop
	Here is an (unoriginal) game for any plural number of players. The game consists of rounds, where every player is the "offense- player" the same predetermined number of rounds. At the beginning of each round, draw an array of dots (vertices of a grid) on a piece of paper, n rows of dots by n columns. (n is a... more » By Leroy Quet  - 1:12am - 2 new of 2 messages

	unique solution of de
	Hi: I am a little bit confused with uniqneness of solution. Say, given a DE below: dy/dt = -a*y with y = y0 at t = t0 and a > 0. The curve of y is an exponentially decay curve for y and t. So its solution is unique: different initial y's leads to different final y's. But when time goes to infinite, the limiting solution is zero. Then... more » By Cheng Cosine  - 12:03am - 4 new of 4 messages

	A problem for the Sylow theorem
	Could I ask 1 more question? Q) Let K be a Sylow p-subgroup of a group G, and N be a normal subgroup of G. Prove that N(intersection)K would be a Sylow p-subgroup of N. OMG... The abstract algebra is too difficult for me... I even can't touch this problem. I miss my analysis... By Kenshin  - Feb 8 - 3 new of 3 messages

	Soduko Theorem
	Proposition. When a game of Soduko is complete, a digit such as 1, will occupy a different position in each of the nine 3x3 squares. True or False? Reasons? By William Elliot  - Feb 8 - 7 new of 7 messages

	Conditions to Have Mean=Median
	Hi, everyone: I am trying to see what the necessary/sufficient conditions on a distribution , to have the mean equal the median. It seems like symmetry is at least sufficient; the normal distribution obviously has this property. In general, it would seem that if there is a value m in the distribution such that , when removing m... more » By Bacle  - Feb 8 - 3 new of 3 messages

	A Little Math / Physics Puzzle: Seeking Generalized Multiple Derivatives of Gaussian Distribution
	I have been trying to find a generalized expression for the multiple derivatives of a Gaussian. Gaussian functions of course have many application in physics and math, and high order derivatives of this Gaussian typically are involved in generating Green functions. I posted this "puzzle" at the link below along with some hints.... more » By Jay R. Yablon  - Feb 8 - 9 new of 9 messages

	exp(-x) = x-1
	Howdi, ' Show that exp(-x) = x-1 has one real solution and solve the x of the form of the infinite series. ' The first part of the problem is really simple just by using the differentiation, but any idea for the second part? By Kenshin  - Feb 8 - 9 new of 9 messages

	Gaussian prime exercise
	Here's an exercise from Rosen's Number Theory text: 14.1.43 Show that if \pi_1=a-1+bi, \pi_2=a+1+bi, \pi_3 = a+(b-1)i, and \pi_4 = a+(b+1)i are all Gaussian primes and |a|+|b| > 5, then 5 divides both a and b and neither a nor b is zero. I'm able to prove the first part, but I'm at a loss to show the "neither a nor b is zero" bit.... more » By Bart Goddard  - Feb 8 - 1 new of 1 message

	smallest constant
	Find the smallest constant k such that (x/Sqrt[x+y]+y/Sqrt[y+z]+z/Sqr t[z+x])<=k*Sqrt[(x+y+z)] for all positive x, y, z. By KY  - Feb 8 - 5 new of 5 messages