Semi-invertible extensions of C*-algebras

TL;DR

This paper extends the class of C*-algebras known to have semi-invertible extensions, including certain amalgamations of algebras and groups, enhancing understanding of their extension properties.

Contribution

It broadens the list of C*-algebras with semi-invertible extensions by analyzing amalgamations of algebras and groups, including reduced and full group C*-algebras.

Findings

Extended semi-invertibility to new classes of C*-algebras

Analyzed amalgamations of C*-algebras and groups

Included both reduced and full group C*-algebras

Abstract

We prolonge the list of C*-algebras for which all extensions by any stable separable C*-algebra are semi-invertible. In particular, we handle certain amalgamations, both of C*-algebras and of groups. Concerning groups we consider both reduced and full group C*-algebras.