English

Every countable group admits amenable actions on stably finite simple C*-algebras

Operator Algebras 2026-02-09 v2 Dynamical Systems Group Theory

Abstract

We give the first examples of (non-amenable group) amenable actions on stably finite simple C*-algebras. More precisely, we give such actions for any countable group in an explicit way. The main ingredients of our construction are the full Fock space of the regular representation and a trace-scaling automorphism.

Keywords

Cite

@article{arxiv.2204.04480,
  title  = {Every countable group admits amenable actions on stably finite simple C*-algebras},
  author = {Yuhei Suzuki},
  journal= {arXiv preprint arXiv:2204.04480},
  year   = {2026}
}

Comments

Minor revisions based on referee report, 8 pages, to appear in American Journal of Mathematics

R2 v1 2026-06-24T10:43:15.116Z