A distributed operational semantics for CCS based on C/E systems

A new set of inference rules for the guarded version of Milner's Calculus of Communicating Systems is proposed. They not only describe the actions agents may perform when in a given state, but also say which parts of the agents move when the global state changes. From the transition relation a particular Petri Net, namely a Condition/Event system called ?ccs, is immediately derived. Our construction gives a semantics which is consistent with the interleaving semantics of CCS and exhibits full parallelism. The proof consists of relating the case graph of Eccs with the original and with the multiset (step) transition systems of the calculus.