Timed Petri nets and timed automata: On the discriminating power of zeno sequences

Timed Petri nets and timed automata are two standard models for the analysis of real-time systems. We study in this paper their relationship, and prove in particular that they are incomparable with respect to language equivalence. In fact, we study the more general model of timed Petri nets with read-arcs (RA-TdPN), already introduced in [J. Srba, Timed-arc petri nets vs. networks of automata, in: Proceedings of the 26th International Conference Application and Theory of Petri Nets (ICATPN 05), Lecture Notes in Computer Science, vol. 3536, Springer, Berlin, 2005, pp. 385–402], which unifies both models of timed Petri nets and of timed automata, and prove that the coverability problem remains decidable for this model. Then, we establish numerous expressiveness results and prove that Zeno behaviours discriminate between several sub-classes of RA-TdPNs. This has surprising consequences on timed automata, for instance, on the power of non-deterministic clock resets.