Symbolic bisimulation for timed processes

Abstract

Basing on symbolic transition systems, we propose a novel approach to the semantics of timed processes. A process algebra in which actions may occur within specified time intervals is introduced, together with a notion of bisimulation equivalence, based on standard transition systems.

The language is also equipped with a new, symbolic operational semantics. The latter, contrary to standard operational semantics, gives rise to transition systems which are finitely branching and, for a large class of processes, finite. On top of the symbolic operational semantics, we introduce a notion of symbolic bisimulation, for which a tractable proof technique exists. We then prove that symbolic and standard bisimulations coincide for our processes. A proof system to reason about bisimilarity is also presented. The soundness and completeness proofs for the system take great advantage of the symbolic characterization of bisimilarity.

Work done while the author was at Istituto per Elaborazione dell'Informazione — CNR, Pisa. The work has been partially supported by EEC, HCM Project Express and by CNR within the project “Specifica ad Alto Livello e Verifica di Sistemi Digitali”.