A Compositional Semantics for Statecharts using Labeled Transition Systems

We characterize the statecharts step semantics of Pnueli and Shalev as a mapping Ψ from an inductively defined algebra of statecharts terms to a domain of labeled transition systems (LTSs). Statecharts equivalence =sc, i.e. LTS isomorphism, is shown not to be a congruence and hence the step semantics is not compositional. We define a new semantic mapping Ψ > to a domain of LTSs with a richer label structure, and show that LTS isomorphism in this domain is the largest congruence contained in =sc.