The Expressiveness of CSP With Priority

The author previously [A.W. Roscoe, On the expressiveness of CSP, https://www.cs.ox.ac.uk/files/1383/expressive.pdf, 2011; A.W. Roscoe, Understanding concurrent systems, Springer 2010] defined 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 [A.W. Roscoe, Understanding concurrent systems, Springer 2010], with the restriction on negative premises removed.