Commodification of accelerations for the Karp and Miller Construction.

International audienceKarp and Miller's algorithm is based on an exploration of the reachability tree of aPetri net where, the sequences of transitions with positive incidence are accelerated. The tree nodes of Karp and Miller are labeled with omega-markings representing (potentially infinite) coverability sets. This set of omega-markings allows us to decide several properties of the Petri net, such as whether a marking is coverable or whether the reachability set is finite.The edges of the Karp and Miller tree are labeled by transitions but the associated semanticis unclear which yields to a complex proof of the algorithm correctness. In this work weintroduce three concepts: abstraction, acceleration and exploration sequence. In particular, we generalize the definition of transitions to omega-transitions in order to represent accelerations by such transitions. The notion of abstraction makes it possible to greatly simplify the proof of the correctness. On the other hand, for an additional cost in memory, which we theoretically evaluated, we proposean ``accelerated" variant of the Karp and Miller algorithm with an expected gain inexecution time. Based on a similar idea we have accelerated (and made complete) the minimal coverability graph construction,implemented it in a tool and performed numerous promising benchmarksissued from realistic case studies and from a random generator of Petri nets