User Peter Kropholler

12 votes

1 answer

654 views

Is there a notion of 'amenable ring'

asked May 27, 2018 at 12:03

12 votes

1 answer

461 views

Group extensions with non-abelian kernel

asked May 6, 2021 at 14:41

12 votes

1 answer

396 views

What is the least $n\ge1$ for which there is an $n$-dimensional closed flat manifold with perfect fundamental group?

asked Dec 22, 2022 at 15:27

11 votes

1 answer

270 views

Example of three dimensional atoroidal Poincaré duality group with some pathology

asked Dec 16, 2023 at 15:18

11 votes

1 answer

1k views

Are condensed vector spaces over finite fields always solid?

asked Jan 14, 2022 at 10:42

9 votes

2 answers

1k views

Sets of algebraic integers whose differences are units

asked Jun 27 at 7:23

8 votes

0 answers

252 views

In search of a quick proof that groups acting freely on $\mathbb R$-trees are linear

asked Dec 21, 2022 at 12:21

8 votes

1 answer

371 views

Calculation of boundary of slant product in W. S. Massey's Singular Homology textbook

asked Jul 30, 2022 at 12:41

6 votes

0 answers

209 views

Amenable groups with all subgroups finitely generated

asked Jun 7, 2020 at 10:48

6 votes

0 answers

374 views

Singular homology using singular cubes

asked Jul 30, 2022 at 12:22

5 votes

0 answers

142 views

Mordell's theorem on rational quadrilaterals

asked Sep 19, 2019 at 13:53

5 votes

0 answers

163 views

Cohomology of a countable directed union of groups

asked Dec 15, 2022 at 11:30

5 votes

0 answers

88 views

Replacing a $G$-CW-complex with a $G$-homotopy equivalent $G$-simplicial complex - can anyone supply a reference?

asked Feb 8 at 20:14

5 votes

1 answer

308 views

Reference request for the group of units of a power series ring in one variable

asked Jul 26, 2023 at 9:05

3 votes

1 answer

150 views

Let $R$ be an associative ring with 1. Let $M$ be a product if infinitely many copies of $R$, viewed as a left $R$-module. Is $M$ locally free?

asked Jun 12 at 14:51

2 votes

1 answer

443 views

Possible characterisation of compactly generated weakly Hausdorff spaces

asked Aug 6, 2022 at 6:42

1 vote

0 answers

127 views

Extremally disconnected sets as building blocks for compact Hausdorff spaces

asked Mar 27 at 11:35

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17 Questions

Is there a notion of 'amenable ring'

Group extensions with non-abelian kernel

What is the least $n\ge1$ for which there is an $n$-dimensional closed flat manifold with perfect fundamental group?

Example of three dimensional atoroidal Poincaré duality group with some pathology

Are condensed vector spaces over finite fields always solid?

Sets of algebraic integers whose differences are units

In search of a quick proof that groups acting freely on $\mathbb R$-trees are linear

Calculation of boundary of slant product in W. S. Massey's Singular Homology textbook

Amenable groups with all subgroups finitely generated

Singular homology using singular cubes

Mordell's theorem on rational quadrilaterals

Cohomology of a countable directed union of groups

Replacing a $G$-CW-complex with a $G$-homotopy equivalent $G$-simplicial complex - can anyone supply a reference?

Reference request for the group of units of a power series ring in one variable

Let $R$ be an associative ring with 1. Let $M$ be a product if infinitely many copies of $R$, viewed as a left $R$-module. Is $M$ locally free?

Possible characterisation of compactly generated weakly Hausdorff spaces

Extremally disconnected sets as building blocks for compact Hausdorff spaces