User Carl-Fredrik Nyberg Brodda

34 votes

What are examples of (collections of) papers which "close" a field?

answered Dec 3, 2019 at 15:45

25 votes

Why is integer factoring hard while determining whether an integer is prime easy?

answered Dec 6, 2022 at 9:37

24 votes

Recognizing free groups

answered Dec 4, 2023 at 0:47

19 votes

Accepted

Number of finite index subgroups in a free abelian group

answered Aug 3, 2022 at 17:36

18 votes

Results from abstract algebra which look wrong (but are true)

answered Jan 20, 2023 at 15:42

17 votes

Are all free monoids residually finite?

answered Jul 20, 2023 at 12:49

17 votes

Decision problems for which it is unknown whether they are decidable

answered Nov 8, 2019 at 10:37

17 votes

Noteworthy, but not so famous conjectures resolved recent years

answered Feb 3, 2019 at 10:20

16 votes

The first female algebraist in US/Britain?

answered Mar 12, 2021 at 12:13

16 votes

Theorems with many distinct proofs

answered Aug 11, 2021 at 15:30

15 votes

Accepted

Explanation for $\chi(\operatorname{SL}_2(\mathbb{Z})) = -1/12$ with zeta function

answered Jan 8, 2022 at 22:03

13 votes

Conceptual reason why the sign of a permutation is well-defined?

answered Mar 9, 2022 at 23:48

13 votes

Comparative analysis of history of mathematics

answered Feb 10, 2023 at 11:00

13 votes

Accepted

Transposition Cayley graphs are planar

answered Apr 28, 2020 at 11:52

12 votes

Accepted

Looking for an electronic copy of Holmgren's old paper

answered Aug 17, 2021 at 21:42

11 votes

Accepted

Cohomology of $\operatorname{GL}_3(\mathbb{F}_2)$

answered Jun 27, 2023 at 13:56

11 votes

Accepted

Reference request: Recent progress on the conjugacy problem for torsion-free one-relator groups?

answered Apr 17, 2020 at 16:25

11 votes

Atlas-like websites on specific areas of mathematics

answered Mar 6, 2020 at 22:22

10 votes

Appearance of proof relevance in "ordinary mathematics?"

answered Jul 25, 2020 at 16:51

10 votes

Which great mathematicians had great political commitments?

answered Feb 22, 2021 at 10:46

10 votes

Analogous results in geometric group theory and Riemannian geometry?

answered Sep 8, 2023 at 6:03

10 votes

When is 4 qualitatively different than $n\leq 3$?

answered Nov 12 at 12:07

9 votes

Accepted

Is the isomorphism problem solvable for torsion-free groups?

answered May 4, 2023 at 6:56

8 votes

Examples of unexpected mathematical images

answered May 21, 2019 at 13:13

7 votes

What is an important mathematical question?

answered Feb 27, 2023 at 11:03

7 votes

Subgroup membership problem in simple groups

answered Mar 22, 2023 at 12:50

7 votes

Examples of long running and consecutively numbered international meetings

answered Oct 30 at 9:39

7 votes

Presentation of special linear group over localizations of the integers

answered Jan 17 at 11:00

7 votes

Centre of orbifold fundamental group of torus (Klein bottle) with one cone point

answered Nov 21, 2022 at 17:29

6 votes

What mathematical formalism might be used to disprove natural selection, on the basis that there are too many independent genetic parameters?

answered Mar 30, 2023 at 6:45

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68 Answers

What are examples of (collections of) papers which "close" a field?

Why is integer factoring hard while determining whether an integer is prime easy?

Recognizing free groups

Number of finite index subgroups in a free abelian group

Results from abstract algebra which look wrong (but are true)

Are all free monoids residually finite?

Decision problems for which it is unknown whether they are decidable

Noteworthy, but not so famous conjectures resolved recent years

The first female algebraist in US/Britain?

Theorems with many distinct proofs

Explanation for $\chi(\operatorname{SL}_2(\mathbb{Z})) = -1/12$ with zeta function

Conceptual reason why the sign of a permutation is well-defined?

Comparative analysis of history of mathematics

Transposition Cayley graphs are planar

Looking for an electronic copy of Holmgren's old paper

Cohomology of $\operatorname{GL}_3(\mathbb{F}_2)$

Reference request: Recent progress on the conjugacy problem for torsion-free one-relator groups?

Atlas-like websites on specific areas of mathematics

Appearance of proof relevance in "ordinary mathematics?"

Which great mathematicians had great political commitments?

Analogous results in geometric group theory and Riemannian geometry?

When is 4 qualitatively different than $n\leq 3$?

Is the isomorphism problem solvable for torsion-free groups?

Examples of unexpected mathematical images

What is an important mathematical question?

Subgroup membership problem in simple groups

Examples of long running and consecutively numbered international meetings

Presentation of special linear group over localizations of the integers

Centre of orbifold fundamental group of torus (Klein bottle) with one cone point

What mathematical formalism might be used to disprove natural selection, on the basis that there are too many independent genetic parameters?