Two Papers on CSP

Abstract

This paper introduces an alternative, coarser, partial order on the (improved) failures model of [BR] (sometimes called the failures divergences model). The new order gives exactly the same semantics to CSP as the old one. As well as being of intrinsic interest for this reason the new order allows one to establish some interesting new results about the semantics of CSP and also (if desired) to extend the model to encompass certain extra forms of unbounded nondeterminism.