Maximal Confluent Processes

In process semantics of Petri Net, a non-sequential process is a concurrent run of the system represented in a partial order-like structure. For transition systems it is possible to define a similar notion of concurrent run by utilising the idea of confluence. Basically a confluent process is an acyclic confluent transition system that is a partial unfolding of the original system. Given a non-confluent transition system G, how to find maximal confluent processes of G is a theoretical problem having many practical applications. In this paper we propose an unfolding procedure for extracting maximal confluent processes from transition systems. The key technique we utilise in the procedure is the construction of granular configuration structures (i.e. a form of event structures) based on diamond-structure information inside transition systems.