Approaching the Coverability Problem Continuously

Abstract. The coverability problem for Petri nets plays a central role in the verification of concurrent shared-memory programs. However, its high EXPSPACE-complete complexity poses a challenge when encoun-tered in real-world instances. In this paper, we develop a new approach to this problem which is primarily based on applying forward coverabil-ity in continuous Petri nets as a pruning criterion inside a backward-coverability framework. A cornerstone of our approach is the efficient encoding of a recently developed polynomial-time algorithm for reacha-bility in continuous Petri nets into SMT. We demonstrate the effective-ness of our approach on standard benchmarks from the literature, which shows that our approach decides significantly more instances than any existing tool and is in addition often much faster, in particular on large instances.