On the Reversibility of Live Equal-Conflict Petri Nets

A Petri net is reversible if its initial marking is a home marking, a marking reachable from any reachable marking. This property is fundamental in man-made systems as it lets a system return to its initial state using only internal operations. Necessary and sufficient conditions are already known for the reversibility of well-formed Choice-Free and ordinary Free-Choice nets. Like the homogeneous Join-Free nets, these nets constitute subclasses of Equal-Conflict nets. In this larger class, the reversibility property is not well understood. This paper provides the first characterization of reversibility for all the live Equal-Conflict systems by extending, in a weaker form, a known condition that applies to the Choice-Free and Free-Choice subclasses. We also show that this condition is tightly related to the Equal-Conflict class and does not apply to several other classes.