Partial order semantics and read arcs

We study a new partial order semantics of Petri nets with read arcs, where read arcs model reading without consuming, which is often more adequate than the destructive-read-and-rewrite modelled in ordinary nets without read arcs. As basic observations we take ST-traces, which are sequences of transition starts and ends. We define processes of our nets and derive two partial orders modelling causality and start precedence. These partial orders are related to basic observations and their system states just as in the ordinary approach the single partial order of a process is related to firing sequences and reachable markings. Our approach also supports a new view of concurrency as captured by steps.

Authors

• Walter Vogler

Keywords

• Concurrency
• Petri nets
• Partial order semantics
• Internal orders
• Szpilrajn's theorem