Ville Salo

Finland

http://villesalo.com

Researcher at University of Turku.

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Units in the group ring over fours group after Gardam

gr.group-theory geometric-group-theory group-rings group-algebras asked Mar 6, 2021 at 10:42

mathoverflow.net

21 votes

Examples of collapsing hierarchies

big-list hierarchy-theorems asked Aug 4, 2020 at 13:45

cstheory.stackexchange.com

16 votes

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

gr.group-theory asked Apr 24, 2018 at 9:27

mathoverflow.net

15 votes

Is homeomorphism of simplicial complexes semidecidable?

gn.general-topology computability-theory asked Sep 13, 2018 at 9:19

mathoverflow.net

13 votes

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

gr.group-theory asked Sep 2, 2019 at 13:42

mathoverflow.net

13 votes

Splendid groups

gr.group-theory topological-groups asked Aug 27, 2020 at 12:26

mathoverflow.net

12 votes

Does the Angel have to be really smart?

computational-complexity combinatorial-game-theory asked Jun 2, 2020 at 1:48

mathoverflow.net

11 votes

Reversible polynomial circuit iff polynomial reversible circuit?

circuit-complexity permutations reversible-computing asked Jan 14, 2019 at 10:39

cstheory.stackexchange.com

10 votes

How can you order a free group?

gr.group-theory order-theory free-groups ordered-groups asked Jan 21, 2020 at 14:10

mathoverflow.net

10 votes

Are modular lattices shallow?

lattice-theory universal-algebra asked Jul 4 at 6:40

mathoverflow.net

Top Answers

For $x$ irrational, is $a_{n} =\sum_{k=1}^{n}(-1)^{⌊kx⌋}$ unbounded?

mathoverflow.net

An aperiodic hexagonal tile?

mathoverflow.net

Does Conway's game of life admit a notion of energy?

mathoverflow.net

Structure theorems for compact sets of rationals

mathoverflow.net

What is the name for a point that is periodic to within $\varepsilon$?

mathoverflow.net

Homeomorphisms and "mod finite"

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Every mathematician has only a few tricks

mathoverflow.net

Is a product of Følner sets Følner?

mathoverflow.net

What is the Borel complexity of this set?

mathoverflow.net

Is there an elementary proof that distal maps are invertible?

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Is there an elementary proof that distal maps are invertible?

mathoverflow.net

Do mixing homeomorphisms on continua have positive entropy?

mathoverflow.net

Word combinatorics terminology question

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A Sauer-Shelah-like lermma for prefix tree

mathoverflow.net

Deciding homomorphic images of De Bruijn graphs

mathoverflow.net

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

mathoverflow.net

Turing machines with all runs decidable

mathoverflow.net

NP-hardness of a sequence problem

mathoverflow.net

A property for a group generated by involutions

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Splendid groups

mathoverflow.net

Chasing game on the Go board

mathoverflow.net

Does $\mathbb{Z}\times\mathbb{Z}$ have an aperiodic monotile?

mathoverflow.net