Structural Reductions Revisited

Structural reductions are a powerful class of techniques that reason on a specification with the goal to reduce it before attempting to explore its behaviors. In this paper we present new structural reduction rules for verification of deadlock freedom and safety properties of Petri nets. These new rules are presented together with a large body of rules found in diverse literature. For some rules we leverage an SMT solver to compute if application conditions are met. We use a CEGAR approach based on progressively refining the classical state equation with new constraints, and memory-less exploration to confirm counter-examples. Extensive experimentation demonstrates the usefulness of this structural verification approach.