User Peter Kropholler

7 votes

Is there a flat manifold with trivial first homology?

answered Nov 27, 2022 at 12:18

6 votes

Group extensions with non-abelian kernel

answered May 8, 2021 at 11:31

5 votes

For a finite-type $\mathbb{Z}$-algebra $A$, is the intersection of all ideals $I$ such that $A/I$ is finite and local necessarily zero?

answered Sep 13, 2022 at 20:23

5 votes

A torsionfree group with infinite cohomological dimension and no infinitely generated free abelian subgroup

answered Dec 27, 2022 at 8:15

4 votes

Is $S^1=\mathbb{R}/\mathbb{Z}$ a ring?

answered Oct 9, 2022 at 13:20

4 votes

Counterexamples in algebra?

answered Aug 12, 2022 at 7:58

4 votes

Subrings, submodules, and flatness

answered Aug 3, 2022 at 14:32

3 votes

Classifications of finite simple objects

answered Dec 30, 2022 at 17:58

3 votes

Accepted

How to quote an numbered equation in a paper

answered Aug 3, 2022 at 6:55

2 votes

Binomial congruence modulo prime

answered Aug 27, 2022 at 17:21

1 vote

In Galois theory, why solvable groups must have their quotient groups be Abelian?

answered Aug 7, 2022 at 8:53

1 vote

Accepted

Are condensed vector spaces over finite fields always solid?

answered Jan 20, 2022 at 14:03

1 vote

Projective dimension of group ring

answered Dec 17, 2022 at 18:08

0 votes

Accepted

Possible characterisation of compactly generated weakly Hausdorff spaces

answered Aug 9, 2022 at 9:55

0 votes

Are two different definitions for Čech cohomology equivalent?

answered Sep 9, 2022 at 6:43

-2 votes

Are there (enough) injectives in condensed abelian groups?

answered Feb 2, 2022 at 12:22

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16 Answers

Is there a flat manifold with trivial first homology?

Group extensions with non-abelian kernel

For a finite-type $\mathbb{Z}$-algebra $A$, is the intersection of all ideals $I$ such that $A/I$ is finite and local necessarily zero?

A torsionfree group with infinite cohomological dimension and no infinitely generated free abelian subgroup

Is $S^1=\mathbb{R}/\mathbb{Z}$ a ring?

Counterexamples in algebra?

Subrings, submodules, and flatness

Classifications of finite simple objects

How to quote an numbered equation in a paper

Binomial congruence modulo prime

In Galois theory, why solvable groups must have their quotient groups be Abelian?

Are condensed vector spaces over finite fields always solid?

Projective dimension of group ring

Possible characterisation of compactly generated weakly Hausdorff spaces

Are two different definitions for Čech cohomology equivalent?

Are there (enough) injectives in condensed abelian groups?