a1 Department of Mathematical Sciences, University of Aberdeen, Aberdeen AB9 2TY, Scotland
a2 Department of Mathematics, Arizona State University, Tempe, AZ85287, USA
A C*-dynamical system is called topologically free if the action satisfies a certain natural condition weaker than freeness. It is shown that if a discrete system is topologically free then the ideal structure of the crossed product algebra is related to that of the original algebra. One consequence is that a minimal topologically free discrete system has a simple reduced crossed product. Sharper results are obtained when the algebra is abelian.
(Received June 27 1992)
* Supported in part by SERC (UK) grant GR/F 74738, and by NSF (USA) grant DMS-9102971.