English

Property $T$ of reduced $C^*$-crossed products by discrete groups

Operator Algebras 2016-09-14 v1

Abstract

We generalize the main result of Kamalov and show that if GG is an amenable discrete group with an action α\alpha on a finite nuclear unital CC^*-algebra AA such that the reduced crossed product Aα,rGA\rtimes_{\alpha,r} G has property TT, then GG is finite and AA is finite dimensional. As an application, an infinite discrete group HH is non-amenable if and only if the uniform Roe algebra Cu(H)C^*_u(H) has property TT.

Keywords

Cite

@article{arxiv.1511.03397,
  title  = {Property $T$ of reduced $C^*$-crossed products by discrete groups},
  author = {Baojie Jiang and Chi-Keung Ng},
  journal= {arXiv preprint arXiv:1511.03397},
  year   = {2016}
}