A TRUE CONCURRENCY MODEL OF CCS SEMANTICS

Degano et al. (1989) introduced AC/E systems (augmented C/E systems) t o give a true concurrency semantics to CCS. But the true concurrency w as not complete. There was no true concurrency for recursive agents (l ike [x].e1\e2) and nondeterminant agents (like e1\e2 + e3\e4). Also th e concept of bisimulation has not been transplanted to AC/E systems. T his paper defines a complete true concurrency model of CCS by exploiti ng the potential concurrency of any CCS agent to its full strength. It introduces a kind of multilayered Petri nets, called NP/R nets, to de fine the processes on AC/E systems. We also introduced the notion of b isimulation of groups of NP/R nets and proved that this bisimulation r elation can determine the CCS bisimulation uniquely.