bio | website | |
---|---|---|
location | Moscow | |
age | 36 | |
visits | member for | 2 years, 10 months |
seen | Jul 19 at 6:55 | |
stats | profile views | 1,050 |
Jun 24 |
comment |
When does a set of collinearity conditions imply collinearity of all of the points?
But what happens if all $n$ points should be distinct? |
Jun 3 |
comment |
Covering fat objects with fat objects
"The slimness factor of a rectangle is identical to its aspect ratio" --- is this true? If you use a square rotated at $\pi/4$, you may cover an $a\times b$ rectangle by a square with side length $(a+b)/\sqrt2$... |
May 29 |
comment |
A functional inequality
@Juanito: Are you sure then that there are no other misses? I am particularly interested in $t>1$ (in your present formulation, you don't say that $g(r^2)>g(r)^2$ --- is it what you wanted?). |
May 28 |
answered | A functional inequality |
May 23 |
comment |
Is there a better proof of this fact in number theory/formal group theory?
Your `ideal' situation provides only $b_n\mid a_n$. Is it enough for you? |
May 22 |
comment |
Quotients of the initial semiring
Recall that there are other homomorphic images of $\mathbb N$, namely the factors by a congruence $\sim_{a,b}$ defined as $x\sim_{a,b}y\iff x,y\geq a \;\wedge\; b\,\mid\,x-y$. A ring $\mathbb Z/n$ corresponds to $\sim_{0,n}$. |
May 14 |
reviewed | Reject suggested edit on nontrivial theorems with trivial proofs |
May 7 |
comment |
“Japanese Theorem” on cyclic polygons: Higher-dimensional generalizations?
What about two decompositions into EQUAL number of simplices? Or (this is more likely to be true) into MINIMAL number of them? |
May 6 |
comment |
Shortest supersequence of all permutations of $n$ elements
See oeis.org/A062714 (and links)... |
May 6 |
comment |
Shortest supersequence of all permutations of $n$ elements
Here is length 12 sequence for $n=4$: 123412314231 |
Apr 14 |
comment |
Simple groups and words
At least, you should add that the word does not contain $n$th power of a word, where $n$ is the period of $S$; otherwise you may have words like $a^kb^na^{n-k}$ etc. |
Apr 1 |
comment |
Square root of a complex matrix commuting with a given one
@GeoffRobinson: Oh yes, ypu are right. Sorry. I have added some words about this case; hopefully now they are correct;)... |
Apr 1 |
revised |
Square root of a complex matrix commuting with a given one
Correction of the last (wrong) statement |
Apr 1 |
revised |
Square root of a complex matrix commuting with a given one
deleted 1 characters in body |
Apr 1 |
answered | Square root of a complex matrix commuting with a given one |
Mar 27 |
answered | Symmetry on a sphere |
Mar 26 |
answered | What is the name for the type of matrices? |
Mar 26 |
comment |
What is the name for the type of matrices?
You may regard $M_{a_1,\dots,a_{2^n}}$ as the `addition table' for $n$-dimensional vector space over $\mathbb F_2$. |
Mar 3 |
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About generalized Minkowski inequality
Recall that the Minkowski inequality turns into equality when $(x_1,\dots,x_n)$ and $(y_1,\dots,y_n)$ are proportional. Thus, if you perturb the function $x^p$ a bit in a neighborhood of some point $a$ (keeping monotonicity, convexity, whatnot) then you may set $a=x_n$ or $a=x_n+y_n$ refuting your inequality for the perturbed function. |
Mar 2 |
comment |
Triangle with largest perimeter in a convex region
Sorry, my previous comment was a result of a miscomputation. The circle is indeed the best among ellipses. |