Proof assistance for real-time systems using an interactive theorem prover

This paper discusses the adaptation of the PVS theorem prover for performing analysis of real-time systems written in the ASTRAL formal specification language. Several issues arose during the encoding of ASTRAL that are relevant to the encoding of many real-time specification languages such as encoding formulas as types, handling partial functions, dealing with noninterleaved concurrency, and defining irregular operators. These issues and possible solutions are presented as well as how they were handled in the ASTRAL encoding. A translator was written that translates any ASTRAL specification into its corresponding PVS encoding. After performing the proofs of several systems using their translations, PVS strategies were developed to automate the proofs of certain types of properties. In particular, strategies are presented for fully automating the proofs of certain classes of untimed properties. In addition, strategies were developed for partially automating the derivation of timed executions using transition steps. The encoding was used as the basis for a fully automated transition sequence generator tool, which has a wide variety of applications.