User Steve D

89 votes

Can a vector space over an infinite field be a finite union of proper subspaces?

answered Feb 5, 2010 at 7:00

71 votes

Examples of eventual counterexamples

answered Feb 16, 2010 at 14:21

60 votes

Quick proofs of hard theorems

answered May 16, 2010 at 22:14

25 votes

Accepted

Half or more elements order two implies generalized dihedral?

answered Sep 26, 2010 at 17:54

23 votes

Can the symmetric groups on sets of different cardinalities be isomorphic?

answered Jan 30, 2010 at 15:12

21 votes

Accepted

An identity for the cosine function

answered Feb 27, 2010 at 11:39

19 votes

Accepted

Seeking Noetherian normal domain with vanishing Picard group but not a UFD

answered May 24, 2010 at 10:35

15 votes

Major mathematical advances past age fifty

answered May 24, 2010 at 22:31

14 votes

Books you would like to see translated into English

answered Mar 11, 2010 at 2:29

13 votes

Accepted

Conjugacy classes intersecting subgroups of finite groups

answered Apr 1, 2010 at 20:15

12 votes

Generating a finite group from elements in each conjugacy class

answered Jun 4, 2010 at 0:09

12 votes

Counterexamples in algebra?

answered Jun 22, 2010 at 0:32

12 votes

Finitely presented sub-groups of $\operatorname{GL}(n,C)$

answered Feb 5, 2010 at 7:28

11 votes

Is there any criteria for whether the automorphism group of G is homomorphic to G itself?

answered Aug 20, 2010 at 9:54

11 votes

Accepted

Is a normal subgroup of a finitely presented group finitely generated or normal finitely genrated?

answered Mar 22, 2010 at 4:35

9 votes

Does injectivity of $\pi_1(\partial U) \to \pi_1(M)$ imply injectivity of $\pi_1(U) \to \pi_1(M)$?

answered Oct 16, 2019 at 22:49

8 votes

Is residual finiteness a profinite property?

answered Mar 14, 2012 at 19:50

8 votes

Accepted

〈x,y : x^p = y^p = (xy)^p = 1〉

answered Apr 24, 2010 at 23:01

7 votes

Deriving a relation in a group based on a presentation

answered Feb 14, 2010 at 14:57

6 votes

Is a compact, connected, orientable 3-manifold with $\mathbb{Z}^K$ fundemental group uniquely determined?

answered Jun 28, 2011 at 5:15

6 votes

Looking for an introductory textbook on algebraic geometry for an undergraduate lecture course

answered Feb 6, 2010 at 12:00

5 votes

less elementary group theory

answered Feb 3, 2010 at 14:58

5 votes

What methods exist to prove that a finitely presented group is finite?

answered Feb 5, 2010 at 7:52

4 votes

decreasing chain of subgroups in the Heisenberg group

answered Feb 5, 2010 at 6:44

4 votes

Accepted

Classification of $p$-groups of order $p^n$ with rank $n-1$

answered Sep 24, 2010 at 20:42

4 votes

FC groups and finite quotients

answered Apr 7, 2012 at 20:38

4 votes

Accepted

Central extension of A4 - Is center torsion-free, and what is rank?

answered Aug 21, 2012 at 0:39

4 votes

Examples of "Monster" groups

answered Jan 9, 2012 at 13:39

3 votes

Subgroups with Infinite cyclic quotients of the Thompons's group

answered Feb 7, 2012 at 3:09

3 votes

When does a subgroup H of a group G have a complement in G?

answered Feb 5, 2010 at 8:30

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36 Answers

Can a vector space over an infinite field be a finite union of proper subspaces?

Examples of eventual counterexamples

Quick proofs of hard theorems

Half or more elements order two implies generalized dihedral?

Can the symmetric groups on sets of different cardinalities be isomorphic?

An identity for the cosine function

Seeking Noetherian normal domain with vanishing Picard group but not a UFD

Major mathematical advances past age fifty

Books you would like to see translated into English

Conjugacy classes intersecting subgroups of finite groups

Generating a finite group from elements in each conjugacy class

Counterexamples in algebra?

Finitely presented sub-groups of $\operatorname{GL}(n,C)$

Is there any criteria for whether the automorphism group of G is homomorphic to G itself?

Is a normal subgroup of a finitely presented group finitely generated or normal finitely genrated?

Does injectivity of $\pi_1(\partial U) \to \pi_1(M)$ imply injectivity of $\pi_1(U) \to \pi_1(M)$?

Is residual finiteness a profinite property?

〈x,y : x^p = y^p = (xy)^p = 1〉

Deriving a relation in a group based on a presentation

Is a compact, connected, orientable 3-manifold with $\mathbb{Z}^K$ fundemental group uniquely determined?

Looking for an introductory textbook on algebraic geometry for an undergraduate lecture course

less elementary group theory

What methods exist to prove that a finitely presented group is finite?

decreasing chain of subgroups in the Heisenberg group

Classification of $p$-groups of order $p^n$ with rank $n-1$

FC groups and finite quotients

Central extension of A4 - Is center torsion-free, and what is rank?

Examples of "Monster" groups

Subgroups with Infinite cyclic quotients of the Thompons's group

When does a subgroup H of a group G have a complement in G?