User Yemon Choi

3 votes

No starter "accessible" well known open problems

answered yesterday

7 votes

Accepted

Closed prime ideal in $C[0, 1]$

answered Apr 10, 2023 at 3:37

7 votes

The sum (with multiplicity) of the cubes of irreducible character degrees of a finite group

answered Feb 23 at 2:32

6 votes

Comparison between the operator norm and the $L^1$ norm on group algebras

answered Nov 5, 2023 at 14:04

5 votes

Accepted

Do completely bounded maps on an operator space have a completely contractive Banach algebra structure?

answered Oct 3, 2023 at 22:32

4 votes

Relationship between noncommutative torus for different values of theta

answered Sep 18, 2023 at 20:24

7 votes

Accepted

Reference request for a preprint by Effros-Ruan

answered Sep 17, 2023 at 23:21

5 votes

Accepted

If $f(x,t)=\sum_{n \in \mathbb{Z}} a_n(t) e^{in x}$ is $C^\infty$ in $x$ and all $a_n(t)$ continuous, $x$ derivatives of $f$ are continuous in $t$?

answered Jul 20, 2023 at 12:55

7 votes

Accepted

When are finite-dimensional representations on Hilbert spaces completely reducible?

answered Jul 14, 2023 at 11:26

3 votes

Accepted

Hardy space inclusion in the right-half plane

answered Jun 21, 2023 at 5:07

8 votes

What are some examples of ingenious, unexpected constructions?

answered Mar 14, 2012 at 16:54

189 votes

Not especially famous, long-open problems which anyone can understand

answered Jun 21, 2012 at 19:38

4 votes

Structure theorem for a class of idempotent monoids (where $xy = x$ or $xy = y$ for all $x, y$)

answered Oct 17, 2022 at 23:45

7 votes

Accepted

Is the matrix induced L1-norm greater than the induced L2-norm?

answered Oct 10, 2022 at 21:11

5 votes

Maximal ideals of the ring $\mathbb C \{T\}$

answered Oct 5, 2022 at 21:07

2 votes

Accepted

A reproducing kernel Hilbert space

answered Aug 16, 2022 at 22:00

1 vote

Accepted

Regarding basis of holomorphic Hardy space

answered Jun 15, 2022 at 22:29

16 votes

Finding questions between functional analysis and set theory

answered Mar 22, 2010 at 17:15

2 votes

Is there analogue of Peter–Weyl theorem for non-compact or quantum group

answered Apr 7, 2010 at 21:58

1 vote

Finiteness of $\ell^2$-Betti numbers

answered May 15, 2022 at 17:20

3 votes

Accepted

Urysohn's lemma for Bochner functions?

answered May 15, 2022 at 17:11

75 votes

Accepted

Which journals publish expository work?

answered Feb 15, 2010 at 21:29

2 votes

Hochschild/cyclic homology of von Neumann algebras: useless?

answered Oct 16, 2009 at 20:45

3 votes

Hochschild/cyclic homology of von Neumann algebras: useless?

answered Oct 19, 2009 at 19:13

2 votes

Hochschild/cyclic homology of von Neumann algebras: useless?

answered Oct 18, 2009 at 5:59

2 votes

Prove that $(v^Tx)^2−(u^Tx)^2\leq \sqrt{1−(u^Tv)^2}$ for any unit vectors $u, v, x$

answered Feb 28, 2022 at 2:56

9 votes

Why are abelian groups amenable?

answered Jan 18, 2010 at 4:05

8 votes

Accepted

Density of matrix coefficients of unitary representations of a locally compact group

answered Dec 27, 2021 at 0:49

12 votes

Defects of Hamel bases for analysis in infinite dimensions

answered Sep 30, 2021 at 2:11

3 votes

When is the annihilator of the commutator subspace a complemented subspace?

answered Sep 24, 2021 at 3:03

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356 Answers

No starter "accessible" well known open problems

Closed prime ideal in $C[0, 1]$

The sum (with multiplicity) of the cubes of irreducible character degrees of a finite group

Comparison between the operator norm and the $L^1$ norm on group algebras

Do completely bounded maps on an operator space have a completely contractive Banach algebra structure?

Relationship between noncommutative torus for different values of theta

Reference request for a preprint by Effros-Ruan

If $f(x,t)=\sum_{n \in \mathbb{Z}} a_n(t) e^{in x}$ is $C^\infty$ in $x$ and all $a_n(t)$ continuous, $x$ derivatives of $f$ are continuous in $t$?

When are finite-dimensional representations on Hilbert spaces completely reducible?

Hardy space inclusion in the right-half plane

What are some examples of ingenious, unexpected constructions?

Not especially famous, long-open problems which anyone can understand

Structure theorem for a class of idempotent monoids (where $xy = x$ or $xy = y$ for all $x, y$)

Is the matrix induced L1-norm greater than the induced L2-norm?

Maximal ideals of the ring $\mathbb C \{T\}$

A reproducing kernel Hilbert space

Regarding basis of holomorphic Hardy space

Finding questions between functional analysis and set theory

Is there analogue of Peter–Weyl theorem for non-compact or quantum group

Finiteness of $\ell^2$-Betti numbers

Urysohn's lemma for Bochner functions?

Which journals publish expository work?

Hochschild/cyclic homology of von Neumann algebras: useless?

Hochschild/cyclic homology of von Neumann algebras: useless?

Hochschild/cyclic homology of von Neumann algebras: useless?

Prove that $(v^Tx)^2−(u^Tx)^2\leq \sqrt{1−(u^Tv)^2}$ for any unit vectors $u, v, x$

Why are abelian groups amenable?

Density of matrix coefficients of unitary representations of a locally compact group

Defects of Hamel bases for analysis in infinite dimensions

When is the annihilator of the commutator subspace a complemented subspace?