On Bisimulations for the Asynchronous pi-calculus
Résumé
The {\em asynchronous $\pi$-calculus\/} is a variant of the $\pi$-calculus where message emission is non-blocking. Honda and Tokoro have studied a semantics for this calculus based on bisimulation. Their bisimulation relies on a modified transition system where, at any moment, a process can perform any input action. In this paper we propose a new notion of bisimulation for the asynchronous $\pi$-calculus, defined on top of the standard labelled transition system. We give several characterizations of this equivalence including one in terms of Honda and Tokoro's bisimulation, and one in terms of %a natural {\em barbed equivalence}. We show that this bisimulation is preserved by name substitutions, hence by input prefix. Finally, we give a complete axiomatization of the (strong) bisimulation for finite terms.