English

Extensions of Quasidiagonal C*-algebras and K-theory

Operator Algebras 2007-05-23 v1

Abstract

We study the extension problem for quasidiagonal (QD) C*-algebras (i.e. when is an extension of QD C*-algebras again QD?). The main positive result states that in many instances an extension will remain QD provided that a certain boundary arising from the K-theory of the extension vanishes. A K-theoretic Hahn-Banach type property is also introduced for QD C*-algebras. We show that every nuclear QD C*-algebra has this Hahn-Banach property if and only if the extension problem for many QD C*-algebras is completely determined by a boundary map on K-theory.

Keywords

Cite

@article{arxiv.math/0008182,
  title  = {Extensions of Quasidiagonal C*-algebras and K-theory},
  author = {N. P. Brown and M. Dadarlat},
  journal= {arXiv preprint arXiv:math/0008182},
  year   = {2007}
}

Comments

Latex, 21 pages