Deriving distributed processes from concurrent processes

In this paper we present a notion of reenement for process algebras motivated by converting an abstract speciication into a concrete implementation. We start with CCS speciications and convert them to speciications with asynchronous message passing. A derived speciication describes an implementation on distributed memory systems. That is individual actions in a CCS process are transformed into processes which may involve explicit message passing actions. As the original speciication and the reened implementation exhibit diierent actions, they cannot be equated under the usual notions of observational equivalence. Hence we introduce a indexed relation, which allows irrelevant actions to be abstracted away. A few properties satissed by the indexed relation are presented.