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HJRW's user avatar
HJRW's user avatar
HJRW
  • Member for 13 years, 7 months
  • Last seen more than a week ago
71 votes
Accepted

$|G|>2$ implies $G$ has non trivial automorphism

42 votes

subgroups of finitely generated groups with a finite index

30 votes

Finding subgroups of a free group with a specific index

9 votes

Epimorphism from GL(2,Z) to GL(2,Z)

8 votes
Accepted

Fundamental group of mapping torus?

8 votes

Index of certain subgroups of the free group $F_2$

8 votes

Finite generation in amalgamated free products

7 votes

Subgroups - Klein bottle

7 votes

Working out a Group Presentation

6 votes

The free group $F_3$ being a quotient of $F_2$

5 votes

Braid groups and representations

5 votes
Accepted

Residual Finiteness of Fundamental Groups of Seifert Fibered Spaces

4 votes
Accepted

Is there a specific name and/or representation for the group of distinguishable orientations of a given shape?

4 votes

Groups that are not amalgams

4 votes

Easy explanation of non-abelianness of hyperbolic curves

4 votes

Groups having at most one subgroup of any given finite index

4 votes

Generators and Relations for $A_4$

3 votes
Accepted

Kernel of $\phi: A * B \to A \times B$ is free

2 votes

Well known proofs that $\mathrm{PSL}_2(\mathbf Z) \cong C_2 * C_3$

2 votes

Product in an non-commutative group

1 vote
Accepted

Limit groups are CSA

0 votes

Algorithms to find simple closed curves on a surface