A Theory of Bisimulation for the-calculus
Abstract:
We study a new formulation of bisimulation for the-calculus [MPW92], which we have called open bisimulation ( ). In contrast with the previously known bisimilarity equivalences, is preserved by all-calculus operators, including input prefix. The differences among all these equivalences already appear in the sublanguage without name restrictions: Here the definition of can be factorised into a "standard " part which, modulo the different syntax of actions, is the CCS bisimulation, and a part specific to the-calculus, which requires name instantiation. Attractive features of are: a simple axiomatisation (of the finite terms), with a completeness proof which leads to the construction of minimal canonical representatives for the equivalence classes of ; an "efficient " characterisation, based on a modified transition system. This characterisation seems promising for the development of automated-verification tools and also shows the call-by-need flavour of. Although in the paper we stick to-calculus, the issues developed may be relevant to value-passing calculi in general.
