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Ville Salo
  • Member for 4 years, 3 months
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21 votes
4 answers
2k views

Units in the group ring over fours group after Gardam

16 votes
3 answers
2k views

If the center of a finite group is trivial, are there two elements whose centralizers intersect trivially?

13 votes
1 answer
586 views

Splendid groups

12 votes
0 answers
269 views

Does the Angel have to be really smart?

12 votes
0 answers
475 views

Is homeomorphism of simplicial complexes semidecidable?

12 votes
1 answer
420 views

Can matrices over $F[G]$ have infinite order when $G$ is periodic?

10 votes
1 answer
581 views

How can you order a free group?

7 votes
4 answers
567 views

Roots in Thompson's groups

6 votes
1 answer
258 views

Which groups contain a comb?

6 votes
1 answer
176 views

Is there a prefix-continuous bijection between finite words and eventually zero words?

6 votes
0 answers
130 views

Difficulty of homeomorphism of effective Cantor dynamics

6 votes
1 answer
252 views

Examples of "natural" finitely generated groups with an undecidable conjugacy problem

6 votes
2 answers
402 views

Which groups are doubling?

4 votes
2 answers
268 views

Reversible polynomial circuit = polynomial reversible circuit?

4 votes
0 answers
149 views

Distortion in the Brin-Thompson 2V

4 votes
1 answer
157 views

Topologically mixing cellular automata on groups

4 votes
0 answers
191 views

Finitely-generated amenable group isomorphic to its square

3 votes
1 answer
186 views

Finitely-generated conjugation action on a subgroup that is not normal... what is that?

3 votes
1 answer
185 views

Convex sets on the discrete Heisenberg group

3 votes
1 answer
159 views

Monotile that tiles when you apply a rubber band

2 votes
0 answers
179 views

$V$-like actions of $V$

2 votes
0 answers
58 views

Are there finitely-presented astral monoids?

2 votes
1 answer
104 views

A detail about busy beaverly behavior of distortion functions in graph groups

1 vote
2 answers
273 views

Impredictable subsets of $\mathbb{N}$

1 vote
1 answer
47 views

If the union of finitely many conjugacy classes is syndetic, are there finitely many conjugacy classes?

1 vote
0 answers
39 views

If the union of finitely many conjugacy classes hits large enough difference sets, are ther finitely many conjugacy classes?

0 votes
0 answers
80 views

QI-closure of $\mathrm{NA}\times\mathrm{NA}$

0 votes
0 answers
42 views

Is there a reversible fully polynomial-time approximation scheme for polygonal billiards?