Rieffel proper actions (Q2835225)

The starting point of this work is a paper by \textit{M. A. Rieffel} [Prog. Math. 84, 141--182 (1991; Zbl 0749.22003)] where a notion of properness for actions of locally compact groups on \(C^\ast\)-algebras is introduced. This concept leads to the construction of generalized fixed-point algebras associated to such actions. The aim of the work under review is to present a characterization of Rieffel proper actions. Some included examples show that a given action might carry different structures for the Rieffel properness, having different generalized fixed-point algebras.