On the reachability and reversibility problems in a class of Petri nets

The paper faces the reachability and the reversibility problems in a class of Petri nets larger than other classes investigated for the same problems. The considered class of Petri net represents a formal language to design and analyze logic controllers. These nets may be decomposed in simple structures, called elementary control tasks, linked together through a limited number of connections, giving rise to arbitrarily complex nets. Such connections are the ones encountered in a typical logic control problem, as exchange of enabling signals (consensus/deny to control maneuvers) and the synchronous execution (shared resources modeling or shared operations). The purpose of the paper is to enlarge the set of theoretical tools previously developed for the incremental approach to the liveness analysis of a net, to be incorporated into a special CAD environment. In particular, the addressed topics are the choice of the initial marking and the analysis of reachability of nonlive markings