A pi-calculus with explicit substitutions

A new formulation of the pi-calculus, where name instantiation is handled explicitly via the introduction of a suitable combinator, is presented. The bisimulation semantics originally developed for the pi-calculus are retrieved by giving the description of the corresponding strategies for name instantiation. The explicit handling of name instantiation allows us to reduce the pi-calculus transitional semantics to a standard SOS framework. Hence, pi-calculus bisimulation models can take fully advantage of the SOS meta-theory developed for 'static' process calculi. For instance, complete axiomatic characterizations of pi-calculus bisimulation equivalences can be automatically derived by turning SOS rules into equations. This formulation of the pi-calculus is very promising for the development of semantic-based automatic verification tools.