University of Cambridge > Talks.cam > Geometric Group Theory (GGT) Seminar > Approximate actions and Ulam stability

Approximate actions and Ulam stability

Add to your list(s) Download to your calendar using vCal

  • UserOren Becker (University of Cambridge)
  • ClockFriday 08 November 2019, 13:45-14:45
  • HouseCMS, MR13.

If you have a question about this talk, please contact .

Given two permutations A and B in Sym(n) such that AB and BA are almost equal, are there A’ and B’ in Sym(n) such that A is close to A’, B is close to B’, and A’B’=B’A’? Arzhantseva and Paunescu formalized this question and gave an affirmative answer: “Nearly commuting permutations are near commuting permutations”. Equivalently, approximate actions of the group Z2 on finite sets are close to genuine actions, i.e., Z2 is stable (in permutations). I will discuss the more general problem: Which finitely generated groups are stable?

This will bring into the picture notions such as Property (T), amenability, invariant random subgroups, sofic groups and property testing.

The talk is based on joint works with Alex Lubotzky, Andreas Thom and Jonathan Mosheiff.

This talk is part of the Geometric Group Theory (GGT) Seminar series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.

 

© 2006-2020 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity