A compositional axiomatization of statecharts

Abstract

Statecharts is a behavioural specification language proposed for specifying large real-time, event-driven, reactive systems. It is a graphical language based on state-transition diagrams for finite state machines extended with many features like hierarchy, concurrency, broadcast communication and time-out. We supply Statecharts with a compositional axiomatization for both safety and liveness properties. By generating external events symbolically, Statecharts can be executed, thereby turning it into a programming language for real-time concurrency (as well as enabling rapid prototyping). As such it is well suited for compositional program verification. In addition to our compositional axiomatic system, we give a denotational semantics and prove that the axiomatization is sound and relatively complete with respect to this semantics.