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. In this paper, we prove that they are incomparable for the timed language equivalence. Thus we propose an extension of timed Petri nets with read-arcs (RA-TdPN), whose coverability problem is decidable. We also show that this model unifies timed Petri nets and timed automata. 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, e.g. on the power of non-deterministic clock resets.