Partial confluence of processes and systems of objects

A process calculus extending the pi-calculus with higher-order agent abstractions as in the Higher-Order Ti-calculus and first-order data other than names but with only first-order interaction is used to give a natural and direct semantic definition for a concurrent object-oriented programming language. A notion of partial confluence of agents is introduced and its theory developed, first in the setting of CCS and then in the mobile-process calculus. It is shown how the semantic definition can be used as a basis for reasoning about systems prescribed by programs of the language: the theory of partial confluence is used to prove the indistinguishability in an arbitrary program context of two classes whose instances combine to form data structures only one of which supports concurrent operations. (C) 1998-Elsevier Science B.V. All rights reserved