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

How many square roots can a non-identity element in a group have?

  • 765
41 votes
1 answer
2k views

Does any set of dominoes tile some common figure?

39 votes
3 answers
2k views

Is there an elementary proof that distal maps are invertible?

  • 1,207
38 votes
5 answers
2k views

Is every path with this property shorter than another path with the same endpoints?

  • 1,967
25 votes
1 answer
668 views

Is the property of not containing $\mathbb{F}_2$ invariant under quasi-isometry?

  • 3,587
19 votes
1 answer
618 views

Is Thompson's group definably orderable?

  • 52k
17 votes
1 answer
338 views

Hopping geodesics

17 votes
1 answer
485 views

Is Thompson's group $T$ co-Hopfian?

17 votes
0 answers
445 views

Does the Ackermann function count something?

  • 171
13 votes
1 answer
438 views

Which convex bodies can be captured in a knot?

13 votes
2 answers
583 views

Is irreducibility of polynomials $\in \mathbb{Z} [X]$ over $\mathbb{Q}$ an undecidable problem?

12 votes
1 answer
373 views

Subwords of the infinite Fibonacci word

10 votes
2 answers
395 views

Sequence of epimorphisms of residually finite groups stabilizes

  • 435
10 votes
1 answer
314 views

Cohomology for extension problems in symbolic/topological dynamics?

9 votes
1 answer
305 views

Diameter of the modified bubble-sort graph

7 votes
0 answers
197 views

Bounded open sets with same boundaries

  • 17.1k
6 votes
0 answers
190 views

2D quadrant sandpile: emergent highway structure

6 votes
1 answer
294 views

Uses for Sharkovskii's theorem

  • 405
6 votes
0 answers
84 views

Construction of minimal zero entropy measure-theoretically strong mixing subshift?

6 votes
2 answers
193 views

Topological dynamical systems with only zero-entropy factors

4 votes
1 answer
106 views

Is it true that $(X,T^k)$ minimal for all $k\geq1$ implies $\mathrm{Aut}(X,T) = \mathrm{Aut}(X,T^k)$ for all $k\geq1$?

  • 165
4 votes
0 answers
143 views

Is the group ring of an amenable group, viewed as multiplicative monoid, amenable?

  • 4,244
4 votes
1 answer
122 views

Ergodic decomposition of the action of a subgroup

3 votes
1 answer
163 views

Bernoulli percolation, infinite path from (0,0) in a "cone"

  • 363
3 votes
1 answer
596 views

Turing machines with all runs decidable

2 votes
1 answer
101 views

Minimum real number for subset sum difference

2 votes
3 answers
616 views

The critical exponent function

2 votes
1 answer
111 views

Busy beaver sequence for a simple tag-like system

  • 1,567
1 vote
1 answer
107 views

Is Toom's rule robust under local but non-on-site noise?

  • 2,619
1 vote
1 answer
115 views

Is there a description of cellular automata in form of sheaves?