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Seva
  • Member for 13 years, 5 months
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49 votes
4 answers
6k views

The maximum of a polynomial on the unit circle

37 votes
4 answers
2k views

"Circular" domination in ${\mathbb R}^4$

28 votes
2 answers
3k views

Erdős-Szekeres for first differences

26 votes
1 answer
804 views

The maximal "nearly convex" function

21 votes
1 answer
1k views

Does $\binom{2n}{n} \equiv 2 \pmod p$ ever hold?

21 votes
2 answers
1k views

The chromatic number of the union of two graphs

19 votes
0 answers
540 views

Why $\gcd \{ {\rm ord}_p(q)\colon q\mid p-1 \}$ likes to be large?

19 votes
4 answers
701 views

The rank of a perturbed triangular matrix

19 votes
1 answer
887 views

Is the norm of a $0-1$ matrix (almost) attained on a $0-1$ vector?

18 votes
1 answer
862 views

What are the products $\prod_{A\subset{\mathbb F}_p\colon |A|=n} \sum_{a\in A} \zeta^a$ equal to?

17 votes
8 answers
10k views

The first eigenvalue of a graph - what does it reflect?

17 votes
4 answers
1k views

A mixing property for finite fields of characteristic $2$

16 votes
3 answers
1k views

Fano plane drawings: embedding PG(2,2) into the real plane

15 votes
1 answer
705 views

The hypercube: $|A {\stackrel2+} E| \ge |A|$?

15 votes
0 answers
443 views

The rank of a "triangle-free" matrix

15 votes
1 answer
651 views

Submodules of $({\mathbb Z}/6{\mathbb Z})^n$ intersecting $\{0,1\}^n$ trivially

15 votes
1 answer
972 views

Sets with both additive and multiplicative gaps

14 votes
1 answer
720 views

Generating function of the Thue-Morse sequence

14 votes
2 answers
2k views

Arithmetic progressions in power sequences

14 votes
3 answers
2k views

When does $P(a−b)=0$ for $a≠b$ ensure $P(0)=0$? (Continued.)

14 votes
1 answer
1k views

How to keep subsets disjoint?

13 votes
2 answers
1k views

An expander (?) graph

13 votes
1 answer
1k views

A delicate elementary inequality

13 votes
1 answer
587 views

Is ${\rm lcm}\{{\rm ord}_p(q)\colon q\mid p-1,\ q>2\}>\sqrt p\ \,$?

13 votes
0 answers
997 views

Pointwise (Hadamard) matrix product and the rank

13 votes
1 answer
454 views

Near-linear mappings from $\mathbb F_p$ to $\mathbb R$

13 votes
2 answers
495 views

Roots of lacunary polynomials over a finite field

12 votes
1 answer
773 views

Quadratic reciprocity for three primes?

12 votes
0 answers
447 views

Around the Erdős-Ginzburg-Ziv theorem

11 votes
0 answers
332 views

"Small" zero divisors in $\mathbb C[\mathbb Z/p\mathbb Z]$

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