Truly concurrent constraint programming

Vineet Gupta, Radha Jagadeesan, Vijay A. Saraswat

Abstract: We study “causality” relationships in Concurrent Constraint Programming: what is observed is not just the conjunction of constraints deposited in the store, but also the causal dependencies between these constraints. We describe a denotational semantics for cc that is fully abstract with respect to observing this “causality” relation on constraints. This semantics preserves more fine-grained structure of computation; in particular the Interleaving Law (a→P)∥(b→Q)=(a→(P∥(b→Q)))(b→(Q∥(a→P))) is not verified ( □ is indeterminate choice). Relationships between such a denotational approach to true concurrency and different powerdomain constructions are explored.