Taking Complete Finite Prefixes To High Level, Symbolically
For researchers in Petri net verification, this work provides a symbolic complete prefix construction for high-level nets, but the results are incremental as they generalize existing techniques.
The paper defines complete finite prefixes for symbolic unfoldings of high-level Petri nets, generalizing the concept from P/T nets. It extends Esparza et al.'s algorithm to a class of safe high-level nets and evaluates it on four benchmark families, also identifying a broader class of nets with infinitely many reachable markings where an adapted cut-off criterion extends the methodology.
Unfoldings are a well known partial-order semantics of P/T Petri nets that can be applied to various model checking or verification problems. For high-level Petri nets, the so-called symbolic unfolding generalizes this notion. A complete finite prefix of a P/T Petri net's unfolding contains all information to verify, e.g., reachability of markings. We unite these two concepts and define complete finite prefixes of the symbolic unfolding of high-level Petri nets. For a class of safe high-level Petri nets, we generalize the well-known algorithm by Esparza et al. for constructing small such prefixes. We evaluate this extended algorithm through a prototype implementation on four novel benchmark families. Additionally, we identify a more general class of nets with infinitely many reachable markings, for which an approach with an adapted cut-off criterion extends the complete prefix methodology, in the sense that the original algorithm cannot be applied to the P/T net represented by a high-level net.