English

Reduced twisted crossed products over C*-simple groups

Operator Algebras 2016-02-05 v1 Dynamical Systems

Abstract

We consider reduced crossed products of twisted C*-dynamical systems over C*-simple groups. We prove there is a bijective correspondence between maximal ideals of the reduced crossed product and maximal invariant ideals of the underlying C*-algebra, and a bijective correspondence between tracial states on the reduced crossed product and invariant tracial states on the underlying C*-algebra. In particular, the reduced crossed product is simple if and only if the underlying C*-algebra has no proper non-trivial invariant ideals, and the reduced crossed product has a unique tracial state if and only if the underlying C*-algebra has a unique invariant tracial state. We also show that the reduced crossed product satisfies an averaging property analogous to Powers' averaging property.

Keywords

Cite

@article{arxiv.1602.01533,
  title  = {Reduced twisted crossed products over C*-simple groups},
  author = {Rasmus Sylvester Bryder and Matthew Kennedy},
  journal= {arXiv preprint arXiv:1602.01533},
  year   = {2016}
}

Comments

16 pages

R2 v1 2026-06-22T12:43:16.011Z