English

Amenable actions on ill-behaved simple C*-algebras

Operator Algebras 2025-03-03 v2 Group Theory

Abstract

By combining R{\o}rdam's construction and the author's previous construction, we provide the first examples of amenable actions of non-amenable groups on simple separable nuclear C*-algebras that are neither stably finite nor purely infinite. For free groups, we also provide unital examples. We arrange the actions so that the crossed products are still simple with both a finite and an infinite projection.

Keywords

Cite

@article{arxiv.2405.10191,
  title  = {Amenable actions on ill-behaved simple C*-algebras},
  author = {Yuhei Suzuki},
  journal= {arXiv preprint arXiv:2405.10191},
  year   = {2025}
}

Comments

22 pages, no mathematical changes but expositions and explanations greatly improved (following referee's comments). Final version, to appear in IMRN

R2 v1 2026-06-28T16:29:41.266Z