(CCS) A mathematical model (a formal language) for descriBing processes, mostly used in the study of parallelism. A CCS program, written in Behaviour expressions syntax denotes a process Behaviour. Programs can Be compared using the notion of oBservational equivalence. ["A Calculus of Communicating Systems", LNCS 92, Springer 1980]. ["Communication and Concurrency", R. Milner, P-H 1989]. (1994-11-29)