English

Quasidiagonal $C^\ast$-algebras and Nonstandard Analysis

Operator Algebras 2007-05-23 v2 Logic

Abstract

Suppose B is an ultraproduct of finite dimensional C^\ast-algebras. We consider mapping and injectability properties for separable C^\ast-algebras into B. In the case of approximately finite C^\ast-algebras, we obtain a classification of these mappings up to inner conjugacy. Using a Theorem of Voiculescu, we show that for nuclear C^\ast-algebras injectability into an ultraproduct of finite dimensional C^\ast-algebras is equivalent to quasidiagonality.

Keywords

Cite

@article{arxiv.math/0209292,
  title  = {Quasidiagonal $C^\ast$-algebras and Nonstandard Analysis},
  author = {F. Javier Thayer},
  journal= {arXiv preprint arXiv:math/0209292},
  year   = {2007}
}

Comments

18 pages Revised introduction, bibliography. Added other corrections

R2 v1 2026-07-22T16:47:50.666Z