Unfolding concurrent well-structured transition systems

Abstract

Our main objective is to combine partial-order methods with verification techniques for infinite-state systems in order to obtain efficient verification algorithms for concurrent infinite-state systems. Partial-order methods are commonly used in the analysis of finite systems consisting of many parallel components. In this paper we propose an extension of these methods to parallel compositions of infinite-state systems. We argue that it is advantageous to model each component by an event structure as this allows us to exhibit the concurrency present implicitly in some infinite-state systems such as automata with queues or counters. We generalize the notion of complete prefix from 1-safe Petri nets to all well-structured transition systems. We give an on-the-fly unfolding algorithm which given event structures representing the components produces an event structure representing their synchronized product. A prototype implementation demonstrates the benefits of our approach. © Springer-Verlag Berlin Heidelberg 2007.