A Pi-Calculus Machine

In this paper we investigate the -calculus guards, proposing a formalism which use exclusively machine tradition concepts: state, resource, transition. The reduction mechanism is similar to the token-game of Petri nets. We provide a multiset semantics for the -calculus by using this formalism. Moreover, our machines have a graphical representation which emphasizes their structure. As a consequence, we give a new improved graphical representation for the asynchronous -calculus. 1 C.S.Calude and G.Stefanescu (eds.). Automata, Logic, and Computability. Special issue dedicated to Professor Sergiu Rudeanu Festschrift