Aalborg Universitetscenter, Inst. for Elektr. Syst., R 86-1, January 1986. Revised Version.
Also in: Acta Informatica, Vol. 24, No. 1, pages 33-55. 1987.
Abstract: COSY (COncurrent SYstem) is a formalism intended to simplify the study of properties of concurrent systems. COSY programs are similar to Petri nets, but are defined by algebraic expressions. A priority relation a<b on actions a and b is roughly interpreted as ``if both a and b might occur, then choose b''. In the paper a formal semantics for COSY, extended by a priority relation, is studied.