The expressiveness of CSP extended by priority (draft)

In previous work [27, 26] the author defined a notion of CSP-like operational semantics whose main restrictions were the automatic promotion of most τ actions, no cloning of running processes, and no negative premises in operational semantic rules. He showed that every operator with such an operational semantics can be translated into CSP and therefore has a semantics in every model of CSP. In this paper we demonstrate that a similar result holds for CSP extended by the priority operator described in Chapter 20 of [26], with the restriction on negative premises almost completely removed. However, since priority is not compositional in most CSP models, the range of such models that support operators with negative premises is limited.