English

Lamplighters over non-amenable groups are not strongly Ulam stable

Representation Theory 2023-01-10 v3 Dynamical Systems Operator Algebras

Abstract

We prove that a wreath product of an abelian group and a non-amenable group is not strongly Ulam stable. Previously this was known for groups containing free subgroups, due to work of Burger, Ozawa and Thom, and for some surface groups, due to work by Kazhdan. We also show that these wreath products are not deformation rigid.

Cite

@article{arxiv.2009.11738,
  title  = {Lamplighters over non-amenable groups are not strongly Ulam stable},
  author = {Andrei Alpeev},
  journal= {arXiv preprint arXiv:2009.11738},
  year   = {2023}
}

Comments

20 pages, minor changes

R2 v1 2026-06-23T18:46:13.079Z