Ergodic Theory and Dynamical Systems

Research Article

Simple C*-crossed products with a unique trace

Erik Bédosa1

a1 Department of Mathematics, University of Oslo, P.b. 1053, 0316 Oslo, Norway

Abstract

Let (α, u) denote a cocycle-crossed action of a discrete group G on a unital C*-algebra A, and B = C*r (A, G, α, u) the associated reduced (twisted) C*-crossed product. We discuss the following problem: when is B a simple C*-algebra with a unique trace? To this aim, we introduce the concept of tracially properly outerness of actions.

(Received June 11 1993)