User Noah Schweber

48 votes

2 answers

6k views

What is the intuition between 1-cocycles (group cohomology)?

asked Feb 24, 2013 at 2:16

47 votes

2 answers

2k views

When should I be doing cohomology?

asked Dec 30, 2014 at 19:22

42 votes

2 answers

958 views

Positive set theory, antifoundation, and the "co-Russell set"

asked Sep 15, 2017 at 22:44

23 votes

1 answer

468 views

Identifying the finite symmetric groups

asked Apr 12, 2021 at 3:40

22 votes

0 answers

255 views

Can a free complete lattice on three generators exist in $\mathsf{NFU}$?

asked Sep 27, 2021 at 0:21

22 votes

1 answer

565 views

What kind of compactness does "expanding $\mathbb{R}$ by constants" have?

asked Oct 12, 2016 at 0:48

19 votes

1 answer

439 views

A model-theoretic question re: Nelson and exponentiation

asked Aug 16, 2018 at 20:21

19 votes

1 answer

653 views

Spanning the reals with a small set - choicelessly

asked Mar 13, 2016 at 23:13

19 votes

1 answer

632 views

Which rings are rings of continuous functions?

asked May 14, 2022 at 18:39

18 votes

1 answer

529 views

The complexity of finiteness

asked Jul 22, 2020 at 21:17

17 votes

0 answers

303 views

"Multiply everything so far, plug into polynomial" - can these always yield primes?

asked May 18, 2022 at 4:19

17 votes

0 answers

275 views

Non-rigid ultrapowers in $\mathsf{ZFC}$

asked Oct 31, 2021 at 22:30

17 votes

2 answers

700 views

Global structure of the Gromov-Hausdorff space

asked Jul 10, 2015 at 6:52

17 votes

0 answers

838 views

What groups are semidirect products of simple groups?

asked Apr 2, 2012 at 1:10

17 votes

3 answers

3k views

Eckmann-Hilton and higher homotopy groups

asked Jun 22, 2012 at 4:19

16 votes

1 answer

229 views

Exponentiation and a weak fragment of arithmetic

asked Oct 14, 2018 at 18:17

16 votes

2 answers

894 views

Is the theory of the category of topological spaces computable?

asked Mar 3, 2019 at 20:09

16 votes

1 answer

294 views

Can we "slightly" change the measure of a set?

asked Dec 27, 2019 at 1:15

16 votes

0 answers

317 views

Another question on changing measure

asked Dec 29, 2019 at 19:42

16 votes

0 answers

249 views

Do we need full $\mathsf{AC}$ to efficiently use (sub)bases?

asked Aug 31, 2020 at 16:52

15 votes

1 answer

704 views

"Pseudovertices" of a triangle

asked Oct 20, 2021 at 0:33

15 votes

1 answer

351 views

Is there an undetermined Banach-Mazur game in ZF?

asked Jan 20, 2020 at 17:52

15 votes

1 answer

398 views

What nice properties does exponentiation have?

asked Dec 31, 2016 at 23:06

14 votes

1 answer

324 views

Reference on standard types

asked Jun 2, 2013 at 1:32

13 votes

1 answer

568 views

The ethics of Borel determinacy

asked May 25, 2015 at 2:07

13 votes

2 answers

559 views

Can a basis for $\mathbb{R}$ be Borel?

asked Mar 16, 2016 at 19:41

13 votes

1 answer

209 views

When was Regularity/Foundation universally adopted?

asked Sep 16, 2017 at 20:53

13 votes

1 answer

474 views

Is there a specific infinitary sentence second-order logic can't capture?

asked Mar 3, 2020 at 20:04

13 votes

0 answers

133 views

When does a structure admit a "bi-elementary" embedding (into anything at all)?

asked Jul 19, 2021 at 20:07

13 votes

1 answer

230 views

Comparing the cardinalities of generic $\mathbb{R}$s

asked Jul 25, 2020 at 18:33

Stack Exchange Network

165 Questions

What is the intuition between 1-cocycles (group cohomology)?

When should I be doing cohomology?

Positive set theory, antifoundation, and the "co-Russell set"

Identifying the finite symmetric groups

Can a free complete lattice on three generators exist in $\mathsf{NFU}$?

What kind of compactness does "expanding $\mathbb{R}$ by constants" have?

A model-theoretic question re: Nelson and exponentiation

Spanning the reals with a small set - choicelessly

Which rings are rings of continuous functions?

The complexity of finiteness

"Multiply everything so far, plug into polynomial" - can these always yield primes?

Non-rigid ultrapowers in $\mathsf{ZFC}$

Global structure of the Gromov-Hausdorff space

What groups are semidirect products of simple groups?

Eckmann-Hilton and higher homotopy groups

Exponentiation and a weak fragment of arithmetic

Is the theory of the category of topological spaces computable?

Can we "slightly" change the measure of a set?

Another question on changing measure

Do we need full $\mathsf{AC}$ to efficiently use (sub)bases?

"Pseudovertices" of a triangle

Is there an undetermined Banach-Mazur game in ZF?

What nice properties does exponentiation have?

Reference on standard types

The ethics of Borel determinacy

Can a basis for $\mathbb{R}$ be Borel?

When was Regularity/Foundation universally adopted?

Is there a specific infinitary sentence second-order logic can't capture?

When does a structure admit a "bi-elementary" embedding (into anything at all)?

Comparing the cardinalities of generic $\mathbb{R}$s