English

Non-commutativity of the central sequence algebra for separable non-type I C$^{\ast}$-algebras

Operator Algebras 2017-05-17 v2

Abstract

We show that if AA is a separable, simple and non-type I C^{\ast} algebra, then for every properly infinite hyperfinite von Neumann algebra MM with separable predual, its Ocneanu ultrapower MMωM'\cap M^{\omega} arises as a sub-quotient of the central sequence algebra F(A)F(A) defined by the second named author. In particular, this answers affirmatively the question of the second named author (Abel Symposium '04): the central sequence C^{\ast}-algebra of the reduced free group C^{\ast}-algebra Cred(F2)C_{\rm{red}}^*(\mathbb{F}_2) is non-commutative.

Keywords

Cite

@article{arxiv.1510.00468,
  title  = {Non-commutativity of the central sequence algebra for separable non-type I C$^{\ast}$-algebras},
  author = {Hiroshi Ando and Eberhard Kirchberg},
  journal= {arXiv preprint arXiv:1510.00468},
  year   = {2017}
}

Comments

15 pages, same as the published version. We added Ozawa's proof (using Kishimoto-Ozawa-Sakai Theorem) of non-commutativity of F(A) in Appendix