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P9403   J.A. Bergstra & Gh. Stefanescu
        "Processes with multiple entries and exits modulo isomorphism and
        modulo bisimulation"


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. [However, this fails to be
a full model for algebra of flownomials due to the lack of the identities
(= empty transitions). The study of the model with empty transitions is
postpone for a later paper.] The main results consist of correct and
complete axiomatisations of process graphs modulo isomorphism and modulo
bisimulation.