Mechanical Veriication of Timed Automata: a Case Study

This paper reports the results of a case study on the feasibility of developing and applying mechanical methods, based on the proof system PVS, to prove propositions about real-time systems speci ed in the LynchVaandrager timed automata model. In using automated provers to prove propositions about systems described by a speci c mathematical model, both the proofs and the proof process can be simpli ed by exploiting the special properties of the mathematical model. This paper presents the PVS speci cation of three theories that underlie the timed automata model, a template for specifying timed automata models in PVS and an example of its instantiation, and both hand proofs and the corresponding PVS proofs of two propositions. It concludes with a discussion of our experience in applying PVS to specify and reason about real-time systems modeled as timed automata.