Semi-invertible extensions of C⁎-algebras

Abstract

We prolong the list of C * -algebras which have the property that all extensions by a stable C * -algebra are semi-invertible. In particular, it is shown to include group C * -algebras, both reduced and full, of certain amalgamated free products of amenable groups, as well as all free products of nuclear C * -algebras with amalgamation over a common nuclear C * -subalgebra.