User Sergei Ivanov - MathOverflow

Sergei Ivanov

Member for 14 years, 1 month
Last seen more than a month ago

pdmi.ras.ru/~svivanov
Saint Petersburg, Russia

24 Questions

Score Activity Newest Views

9 votes

1 answer

308 views

Convex body with affine-equivalent cross-sections

asked Mar 10, 2016 at 22:21

30 votes

2 answers

3k views

An unfair marriage lemma

asked Apr 23, 2015 at 18:14

24 votes

3 answers

1k views

Isoperimetric inequality on a Riemannian sphere

asked May 5, 2013 at 20:31

14 votes

1 answer

2k views

Invariance of the l.h.s. of Euler-Lagrange equation

asked Apr 2, 2013 at 14:52

18 votes

5 answers

2k views

Smoothness of $f(\sqrt x)$

asked Oct 4, 2011 at 10:19

14 votes

1 answer

582 views

Rational approximations on the circle

asked Apr 19, 2011 at 9:57

9 votes

3 answers

691 views

surfaces of constant centro-affine curvature

asked Apr 13, 2011 at 23:19

20 votes

1 answer

891 views

A collection of intervals that can cover any measure zero set

asked Dec 7, 2010 at 11:43

26 votes

2 answers

2k views

A set that can be covered by arbitrarily small intervals

asked Dec 6, 2010 at 16:05

16 votes

1 answer

504 views

Subdividing a polyhedral space into convex simplices

asked Nov 16, 2010 at 0:31

13 votes

3 answers

1k views

Metric angles in Riemannian manifolds of low regularity

asked Oct 11, 2010 at 18:07

26 votes

6 answers

3k views

Easy proof of the fact that isotropic spaces are Euclidean

asked Oct 5, 2010 at 21:52

24 votes

1 answer

3k views

What can be tiled by T-tetrominoes?

asked Jun 20, 2010 at 20:18

8 votes

2 answers

384 views

Are there arbitrarily sparse "lattices" in negatively curved symmetric spaces?

asked May 29, 2010 at 22:20

10 votes

2 answers

1k views

Are operators with trivial spectrum nilpotent in a sense?

asked May 15, 2010 at 8:41

17 votes

3 answers

2k views

Is there Domain Invariance for Alexandrov spaces?

asked Apr 15, 2010 at 22:34

25 votes

3 answers

2k views

Are fundamental groups of aspherical manifolds Hopfian?

asked Apr 9, 2010 at 12:16

7 votes

3 answers

614 views

Is it decidable whether a given set generates the whole group?

asked Apr 4, 2010 at 21:11

11 votes

1 answer

1k views

In a locally CAT(k) space, does uniqueness of geodesics imply the lack of conjugate points?

asked Mar 30, 2010 at 23:20

32 votes

1 answer

4k views

Is every smooth function Lebesgue-Lebesgue measurable?

asked Mar 26, 2010 at 20:44

6 votes

5 answers

2k views

A book explaining power and limitations of Peano Axioms?

asked Mar 21, 2010 at 11:37

13 votes

3 answers

3k views

Contractible manifold with boundary - is it a disc?

asked Mar 19, 2010 at 22:03

58 votes

9 answers

8k views

How do they verify a verifier of formalized proofs?

asked Mar 16, 2010 at 20:48

8 votes

1 answer

379 views

Estimating flat norm distance from a planar disc

asked Mar 11, 2010 at 22:29