Calculus of Communicating Systems (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)