A classification of the expressive power of well-structured transition systems

We compare the expressive power of a class of well-structured transition systems that includes relational automata, Petri nets, lossy channel systems, constrained multiset rewriting systems, and data nets. For each one of these models we study the class of languages generated by labelled transition systems describing their semantics. We consider here two types of accepting conditions: coverability and reachability of a fixed a priori configuration. In both cases we obtain a strict hierarchy in which constrained multiset rewriting systems is the the most expressive model.