Operational Semantics formally proven in HOL-CSP

Benoît Ballenghien 📧 and Burkhart Wolff 📧

December 24, 2023


Recently, a modern version of Roscoe and Brookes Failure-Divergence Semantics for CSP has been formalized in Isabelle (HOL-CSP) and extended (HOL-CSPM). The resulting framework is purely denotational and, given the possibility to define arbitrary events in a HOL-type, more expressive than the original. However, there is a need for an operational semantics for CSP. From the latter, model-checkers, symbolic execution engines for test-case generators, and animators and simulators can be constructed. In the literature, a few versions of operational semantics for CSP have been proposed, where it is assumed, of course, that denotational and operational constructs coincide, but this is not obvious at first glance. The present work addresses this issue by providing the first (to our knowledge) formal theory of operational behavior derived from HOL-CSP via a bridge definition between the denotational and the operational semantics. In fact, several possibilities are discussed. As a bonus, we have defined three new operators: Sliding, Throw and Interrupt which are of particular pragmatic interest in operational semantics. Moreover, we have proven new laws for HOL-CSP improving the latter.


BSD License


Session HOL-CSP_OpSem