Section: Scientific Foundations

Rewriting-based Safety Checking

Invariant checking and strenghtening is the dual of reachability analysis, and can thus be used for verifying safety properties of infinite-state systems. In fact, many infinite-state systems are just parameterized systems which become finite state systems when parameters are instantiated. Then, the challenge is to automatically discharge the maximal number of proof obligations coming from the decomposition of the invariance conditions. For parameterized systems, we develop a deductive approach where states are defined by first order formulae with equality, and proof obligations are checked by the automatic theorem prover haRVey . Thanks to this tool, we study the applicability of the superposition calculus (a modern version of resolution with a built-in treatment of the equality predicate and powerful techniques for reducing the search space) for deciding conditions arising from program verification.