bio | website | |
---|---|---|
location | Moscow | |
age | 37 | |
visits | member for | 3 years, 8 months |
seen | 2 days ago | |
stats | profile views | 1,419 |
May 8 |
answered | Are There Infinitly Many $n$ Which $a\times n!+1$ Be Composite? |
Apr 22 |
comment |
Create matrix containing values in [0,1] where sum of all diagonals and anti-diagonals is fixed
These conditions are always dependent, and not only due to the sum of all elements. E.g., the sum of all elements with the even sum of indices can be expressed both via $a_i$ and via $b_i$. |
Apr 22 |
comment |
A digraph related to permutations
Sure, you're welcome;) |
Apr 22 |
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A digraph related to permutations
Each Hamiltonian path prolongates to a Hamiltonian cycle exactly for the same reason as the complete domino chain has the same numbers on both ends: a Hamiltonian cycle is an Eulerian path in a graph on the permutations of $n-1$ symbols. |
Apr 8 |
comment |
Diameter of sum-graph over a non-meager set
In the first claim, a number $z$ may happen to be negative... |
Apr 5 |
comment |
The diameter of a certain graph on the positive integers
Pitifully, $a$ and $a+1$ are never at distance 2. |
Mar 29 |
answered | Angle subtended by the shortest segment that bisects the area of a convex polygon |
Mar 28 |
awarded | Nice Question |
Mar 24 |
comment |
Uninteresting questions with interesting answers
Hm... When do the approximants for $\pi$ appear in such way? |
Feb 23 |
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Find a polynomial not in any ideal generated by polynomials of total degree $o(n)$
What if $f_1=1$? |
Feb 1 |
comment |
Sets of points containing permutations - a Ramsey-type question
Still, perhaps it would be better to wait for a more sharp estimate. It is interesting to know the asymptotics of $N=N(k)$ such that in every black and white coloring of $N\times N$ square one of the colors contains every $k$-permutation. Not speaking on more colors... |
Jan 31 |
answered | Sets of points containing permutations - a Ramsey-type question |
Jan 28 |
comment |
Can all unit-distance graphs have their vertices at algebraic integers?
Thanks! The link to the first one was in my answer, but I did not know about the second. |
Jan 27 |
awarded | Nice Answer |
Jan 27 |
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Can all unit-distance graphs have their vertices at algebraic integers?
@David: Do you know the exact reference? |
Jan 26 |
revised |
Can all unit-distance graphs have their vertices at algebraic integers?
Remark has been expanded |
Jan 26 |
answered | Can all unit-distance graphs have their vertices at algebraic integers? |
Jan 26 |
comment |
Can all unit-distance graphs have their vertices at algebraic integers?
@Dima: Not much difference. A hexagonal lattice maps to $K_3$... |
Jan 26 |
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Irreducibility of a polynomial
Sorry, I do not understand why this question is closed. |
Jan 26 |
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Can all unit-distance graphs have their vertices at algebraic integers?
@Dima: I just meant that two such roots with a zero form a triangle. So you may consider homomorphisms to a 6-wheel (which pass to $K_3$ though). |