Processes with multiple entries and exits

Abstract

This paper is an attempt to integrate the algebra of communicating processes (ACP) and the algebra of flownomials (AF). Basically, this means to combine axiomatized parallel and looping operators. To this end we introduce a model of process graphs with multiple entries and exits. In this model the usual operations of both algebras are defined, e.g. alternative composition (this covers both the sum of ACP and the disjoint sum of AF), sequential composition, feedback, parallel composition, left merge, communication merge, encapsulation, etc. The main results consist of correct and complete axiomatisations of process graphs modulo isomorphism and modulo bisimulation.