Formal verification of complex systems using high-level Petri Nets faces the so-called state-space explosion problem. In the
context of Petri nets generated from a higher level specification, this problem is particularly acute due to the inherent
size of the considered models. A solution is to perform a symbolic analysis of the reachability graph, which exploits the
symmetry of a model.
Well-Formed Nets (WN) are a class of high-level Petri nets, developed specifically to allow automatic construction of a symbolic reachability
graph (SRG), that represents equivalence classes of states. This relies on the definition by the modeler of the symmetries of the model, through the definition of “static sub-classes”. Since a model is self-contained, these (a)symmetries
are actually defined by the model itself.
This paper presents an algorithm capable of automatically extracting the symmetries inherent to a model, thus allowing its
symbolic study by translating it toWN. The computation starts from the assumption that the model is entirely symmetric, then examines each component of a net to
deduce the symmetry break it induces. This translation is transparent to the end-user, and is implemented as a service for
the AMI-Net package. It is particularly adapted to models containing large value domains, yielding combinatorial gain in the
size of the reachability graph.
Keywords Well-Formed Petri nets - symmetry detection - symbolic model-checking - partial symmetry