User YCor

20 votes

Accepted

Finitely generated matrix groups whose eigenvalues are all algebraic

answered Apr 1, 2019 at 22:00

20 votes

Accepted

Existence of infinite groups that are too reluctant to be topological

answered May 10, 2014 at 20:54

20 votes

Accepted

Subgroup of hyperbolic group generated by non-torsion elements

answered Feb 13, 2018 at 19:03

20 votes

Accepted

Topological semi-direct products of groups

answered Jun 27, 2022 at 9:05

19 votes

Accepted

Minimal number of generators for $GL(n,\mathbb{Z})$

answered Sep 20, 2014 at 18:22

19 votes

Accepted

Is the identity function a unique multiplicative homeomorphism of $\mathbb N$?

answered Sep 8, 2018 at 22:10

18 votes

Accepted

Finite-dimensional faithful unitary representations of SL(2,Z)

answered Aug 24, 2018 at 22:52

18 votes

Accepted

Is residual finiteness a quasi isometry invariant for f.g. groups?

answered Mar 2, 2019 at 11:49

18 votes

Accepted

Is there a compact, connected, totally path-disconnected topological group?

answered Mar 8, 2020 at 8:31

18 votes

Accepted

Number of $3\times 3$ anticommuting matrices over finite fields $\mathbb{F}_p$ is (or is not?) polynomial in $p$?

answered Sep 26, 2021 at 11:30

17 votes

Is there an absolute geometry that underlies spherical, Euclidean and hyperbolic geometry?

answered Jan 12 at 23:52

17 votes

Are unitarily equivalent permutation matrices permutation similar?

answered Dec 10, 2019 at 15:50

17 votes

What are the main open problems in the theory of amenability of groups?

answered Aug 18, 2021 at 17:24

17 votes

What are the main open problems in the theory of amenability of groups?

answered Aug 18, 2021 at 21:43

17 votes

Accepted

Profinite completion of finitely presented groups

answered Sep 14, 2018 at 20:34

17 votes

Accepted

Finitely generated soluble groups with uncountably many maximal subgroups

answered Sep 5, 2016 at 17:04

16 votes

Accepted

An endomorphism of free groups

answered Sep 25, 2017 at 8:00

16 votes

Accepted

Can you decide whether the commutator subgroup of a f.p. group is f.g?

answered Mar 23, 2015 at 23:41

16 votes

Accepted

Cantor-Bernstein for quasi-isometric embeddings?

answered Nov 1, 2014 at 23:17

16 votes

Accepted

How to construct a group with specified growth function

answered Dec 8, 2013 at 22:00

16 votes

Groups acting on trees

answered Mar 1, 2019 at 23:15

16 votes

Accepted

Which group do two generic $2\times 2$ triangular matrices generate?

answered Dec 5, 2019 at 8:55

16 votes

Accepted

Does $\mathrm{SO}(3)$ act faithfully on a countable set?

answered Sep 6, 2021 at 8:49

16 votes

Is $O_n({\bf Q})$ dense in $O_n({\bf R})$?

answered Jan 16, 2021 at 10:46

16 votes

Multiplicative groups of skew fields

answered Nov 1, 2021 at 23:43

15 votes

Accepted

The group of isometries of a manifold is a Lie group, isn't it?

answered Nov 2, 2020 at 23:44

15 votes

Examples of common false beliefs in mathematics

answered Apr 22, 2020 at 22:35

15 votes

Is the set of all ICC amenable groups countable?

answered Aug 28, 2020 at 8:33

15 votes

$GL_n(\Bbb Z_p)$ conjugacy classes in a $GL_n(\Bbb Q_p)$ conjugacy class

answered Nov 11, 2018 at 21:00

15 votes

Does $\text{Sym}(\omega)$ have $2^{\aleph_0}$ pairwise non-isomorphic subgroups?

answered Jun 3, 2018 at 7:07

Stack Exchange Network

750 Answers

Finitely generated matrix groups whose eigenvalues are all algebraic

Existence of infinite groups that are too reluctant to be topological

Subgroup of hyperbolic group generated by non-torsion elements

Topological semi-direct products of groups

Minimal number of generators for $GL(n,\mathbb{Z})$

Is the identity function a unique multiplicative homeomorphism of $\mathbb N$?

Finite-dimensional faithful unitary representations of SL(2,Z)

Is residual finiteness a quasi isometry invariant for f.g. groups?

Is there a compact, connected, totally path-disconnected topological group?

Number of $3\times 3$ anticommuting matrices over finite fields $\mathbb{F}_p$ is (or is not?) polynomial in $p$?

Is there an absolute geometry that underlies spherical, Euclidean and hyperbolic geometry?

Are unitarily equivalent permutation matrices permutation similar?

What are the main open problems in the theory of amenability of groups?

What are the main open problems in the theory of amenability of groups?

Profinite completion of finitely presented groups

Finitely generated soluble groups with uncountably many maximal subgroups

An endomorphism of free groups

Can you decide whether the commutator subgroup of a f.p. group is f.g?

Cantor-Bernstein for quasi-isometric embeddings?

How to construct a group with specified growth function

Groups acting on trees

Which group do two generic $2\times 2$ triangular matrices generate?

Does $\mathrm{SO}(3)$ act faithfully on a countable set?

Is $O_n({\bf Q})$ dense in $O_n({\bf R})$?

Multiplicative groups of skew fields

The group of isometries of a manifold is a Lie group, isn't it?

Examples of common false beliefs in mathematics

Is the set of all ICC amenable groups countable?

$GL_n(\Bbb Z_p)$ conjugacy classes in a $GL_n(\Bbb Q_p)$ conjugacy class

Does $\text{Sym}(\omega)$ have $2^{\aleph_0}$ pairwise non-isomorphic subgroups?