An Algebraic Semantics for Message Sequence Chart

Message Sequence Charts MSCs are a graphical and textual language for the speci cation of message passing systems in particular telecommunication systems MSCs are standardised by the Internal Telecommunication Union in standard Z Included in the standard is a formal semantics for MSCs by means of a process algebra This semantics covers the complete language of single MSCs but lacks an interpretation for conditions which are used as continuation points of MSCs within an MSC document a collection of MSCs In this paper we give a process algebraic semantics for basic MSCs including conditions enabling the formal interpretation of entire MSC documents