User Andreas Thom

6 votes

Is $\widehat{\mathbb{Z}}[[t]]\cong\widehat{\mathbb{Z}}[[\widehat{\mathbb{Z}}]]$?

answered Feb 7, 2017 at 8:12

5 votes

Accepted

Can an amenable group have a weak mixing unitary representation without almost invariant vectors?

answered Apr 18, 2017 at 8:39

5 votes

Accepted

Kazhdan constant and finite index subgroups

answered Mar 12, 2018 at 15:09

5 votes

Telling group algebras apart

answered Aug 16, 2010 at 19:58

5 votes

Spectrum of the sum of generators for irrational rotation algebra

answered Aug 17, 2010 at 15:00

5 votes

Accepted

Is every countable well-order embeddable in \mathbb{R}?

answered Oct 29, 2010 at 11:04

5 votes

Question on the index of abelianization of groups

answered Dec 4, 2010 at 12:42

5 votes

What $Re(f(z))=c$ can be if $f$ is a holomorphic function ?

answered Nov 26, 2010 at 6:30

5 votes

Is Deligne's central extension sofic?

answered Dec 8, 2010 at 19:48

5 votes

Is "subamenable" the same as amenable?

answered Nov 14, 2010 at 17:44

5 votes

"Probabilistic ultrafilters?"

answered Mar 7, 2011 at 6:16

5 votes

Intrinsically measurable subsets of amenable semigroups.

answered May 21, 2011 at 15:16

5 votes

A matrix algebra has no deformations?

answered Nov 16, 2011 at 8:23

5 votes

residually finite-by-$\mathbb{Z}$ groups are residually finite

answered Oct 17, 2011 at 14:37

5 votes

Accepted

Is $\mathbb R[x,y]_+$ countably generated as a quadratic module?

answered Aug 11, 2014 at 13:01

5 votes

Accepted

Characterizing residually amenable groups

answered Dec 29, 2014 at 7:54

5 votes

Accepted

Simultaneous decomposition of three projectors

answered May 29, 2012 at 7:42

5 votes

mapping space between classifying spaces

answered Feb 11, 2013 at 14:09

5 votes

Accepted

Conjugacy classes and reduced group $C^*$-algebra of an amenable group

answered Feb 18, 2013 at 15:24

4 votes

pointwise ergodic theorem and mean sojourn time

answered Feb 8, 2013 at 12:04

4 votes

Commutator Subgroup - Group Theory

answered Jul 9, 2012 at 19:17

4 votes

Kuiper's theorem via approximation

answered Jul 9, 2012 at 20:01

4 votes

Accepted

States with a unique state extension

answered Nov 8, 2014 at 17:30

4 votes

Which polynomials are determinants of a symmetric matrix with linear entries?

answered Sep 12, 2011 at 1:14

4 votes

Accepted

Lifting of a ucp map with values in a von Neumann algebra ultraproduct of matrix algebras

answered Jul 1, 2011 at 18:15

4 votes

Finite subgroups of unitary groups

answered Apr 21, 2011 at 7:04

4 votes

Discrete groups G whose full C-algebra C(G) is not quasidiagonal?

answered Jun 12, 2011 at 21:54

4 votes

Discrete-compact duality for nonabelian groups

answered Jul 22, 2011 at 21:05

4 votes

Accepted

Do unitary bijections act invariantly on irreducible representations?

answered Feb 9, 2011 at 22:40

4 votes

Accepted

Maximal localizations of von Neumann algebras

answered Aug 5, 2010 at 14:47

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167 Answers

Is $\widehat{\mathbb{Z}}[[t]]\cong\widehat{\mathbb{Z}}[[\widehat{\mathbb{Z}}]]$?

Can an amenable group have a weak mixing unitary representation without almost invariant vectors?

Kazhdan constant and finite index subgroups

Telling group algebras apart

Spectrum of the sum of generators for irrational rotation algebra

Is every countable well-order embeddable in \mathbb{R}?

Question on the index of abelianization of groups

What $Re(f(z))=c$ can be if $f$ is a holomorphic function ?

Is Deligne's central extension sofic?

Is "subamenable" the same as amenable?

"Probabilistic ultrafilters?"

Intrinsically measurable subsets of amenable semigroups.

A matrix algebra has no deformations?

residually finite-by-$\mathbb{Z}$ groups are residually finite

Is $\mathbb R[x,y]_+$ countably generated as a quadratic module?

Characterizing residually amenable groups

Simultaneous decomposition of three projectors

mapping space between classifying spaces

Conjugacy classes and reduced group $C^*$-algebra of an amenable group

pointwise ergodic theorem and mean sojourn time

Commutator Subgroup - Group Theory

Kuiper's theorem via approximation

States with a unique state extension

Which polynomials are determinants of a symmetric matrix with linear entries?

Lifting of a ucp map with values in a von Neumann algebra ultraproduct of matrix algebras

Finite subgroups of unitary groups

Discrete groups G whose full C-algebra C(G) is not quasidiagonal?

Discrete-compact duality for nonabelian groups

Do unitary bijections act invariantly on irreducible representations?

Maximal localizations of von Neumann algebras