4,578 reputation
916
bio website motls.blogspot.com
location Czech Republic
age 40
visits member for 3 years, 2 months
seen 6 hours ago

Hi, I am a string theorist and a publicist.


May
24
comment How to understand and appreciate the prime number industry?
Lowest prime whose factors are not obvious? I thought that the factors of any prime $p$ are obvious, namely $1$ and $p$. ;-)
May
24
comment Fibration $v:S^1 \to \mathbb{R}P^1$ and a nontrivial element of $\pi_1(\mathbb{R}P^n,\ast)$
Unless there's some formal catch, I agree with @user8268. The circle $S^1$ is wrapped "twice" - from a point to the opposite point of the higher-dimensional sphere and back. This is a trivial path/submanifold both in homotopy and homology, isn't it? That's twice of the generator of the $Z_2$ group.
May
24
comment Linear Algebra Question
It was a pleasure, @MAxcoder. Thanks for your bounty. ;-)
May
24
comment AES Key Scheduler
Hi, look at en.wikipedia.org/wiki/Rijndael_key_schedule#Rcon
May
24
answered Simple (even toy) examples for uses of Ordinals?
May
24
comment Function growth comparison
Compare the $n$th root of these two functions. For the left one, it goes to $10/8$ because the difference between $n$, $n-2$, and $n+3$ becomes negligible when taking the roots, and for the right one, it goes to $\log(n)^5$. The latter is ultimately greater than $10/8$, so its $n$th power is also larger.
May
24
answered relations between root lattice and weight lattice
May
24
revised Finding Lagrange's form of the remainder with $a = \pi/2$ and $n\to\infty$
Dollar signs added around maths, nothing else
May
24
suggested suggested edit on Finding Lagrange's form of the remainder with $a = \pi/2$ and $n\to\infty$
May
24
revised A question about integral quadratic forms
Math put in dollar signs, no other edits
May
24
suggested suggested edit on A question about integral quadratic forms
May
23
comment Generalized “Worm on the rubber band ” problem
@Theo, this implicit isomorphism was just an expression of my lack of interest about the identity of the small guy. ;-) @Jean-Pierre, the result looks qualitatively OK for the situations I know - I just didn't know that you could integrate it in general. So I guess that for general functions $a,b$ it's wrong. Which $a,b$ are you substituting to the result if $a,b$ are whole functions of time? I don't really understand what you mean in that case.
May
23
comment Subtract gravity from 3D object in different orientations
Dear Steven, a detail, a typo: the operation is called "subtraction", not "substraction". ;-) Unfortunately, I don't understand what the question wants to say unless your desire is to subtract one 3-vector from another 3-vector.
May
23
answered Intersecting a polygon with four points
May
22
answered Laurent Series and annular regions
May
22
comment The graph of $x^{n}+y^{n}=r^{n}$ for sufficiently large $n$
In other words, for large even $n$, $x^n+y^n=1$ is essentially equivalent to $x\approx \pm 1$ or $y\approx \pm 1$ (with the other variable allowed to be essentially anything), which are the equations of the square. Note that neither $x$ nor $y$ can exceed one, so that's why you only get the 4 line segments.
May
22
comment The graph of $x^{n}+y^{n}=r^{n}$ for sufficiently large $n$
Let me say an answer using basic maths. Without a loss of generality, assume $r=1$; a different value of $r$ simply scales the picture. More importantly, If $n$ is very large and $x$ or $y$ are smaller than one, then $x^n$ and $y^n$ are much smaller than one - they're virtually zero, unless $x$ or $y$ are extremely close to one. For example, $0.9^{100}$ is still close to zero. So if $x^n+y^n=1$, then either $x$ or $y$ or both have to be extremely close to 1 from below so that the high power contributes almost one.
May
21
comment Interesting properties for numbers 1-20?
If you think that no numbers are interesting for any other reason, than 1 is the smallest positive integer that is uninteresting, 2 is the smallest positive integer among the uninteresting ones that is not the smallest uninteresting integer, 3 is the smallest positive integer among the uninteresting ones that is neither the smallest uninteresting integer, nor the smallest positive integer among the uninteresting ones that is not the smallest uninteresting integer, and so on. ;-)
May
21
answered Generalized “Worm on the rubber band ” problem
May
21
answered Binomial formula in $GF(2^m)$