A Process Algebra for Synchronous

Concurrent constraint programming is classically based on asynchronous communication via a shared store. Synchrony can be achieved by forcing concurrently running ask and tell primitives to synchronise on \new common information". This paper outlines this framework, called Scc, and develops an algebraic semantics for it. The Scc framework is shown to share similarities with both the traditional concurrent constraint setting and algebraic languages like CCS but also to have major diierences which requires the use of new techniques in formulating the algebraic semantics. Among these are the introduction of an auxiliary communication operator to handle the treatment of synchrony and the extension of the concept of cylindric algebras by allowing the hiding of the empty set of variables in order to permit local computations. More importantly, new axioms have been introduced to describe our variants of the tell and ask primitives. The algebraic semantics is proved to be sound and complete with respect to a compo-sitional operational semantics which is also presented in the paper.