The fusion calculus is used to model concurrent constraint programming. It is a generalization and simplification of the \(\pi\)-calculus. The heart of the calculus is the fusion action, which in interplay with the scope operator can identify names shared between several processes in the system. Three basic variants of the \(\rho\)-calculus which is a foundational calculus for the concurrent constraint programming language OZ, are encoded in the fusion calculus. Namely, \(\rho(x=y)\) which uses constraints over name equations and conjunction, \(\rho(x=y, C)\) which adds constants to the constraint system and \(\rho(x=y, x \neq y)\) which adds inequalities. Using a new reduction-based semantics and weak barbed congruence for the fusion calculus, an operational correspondence between the \(\rho\)-calculi and their encodings is established. These barbed congruences are shown to coincide with the hyperequivalences previously adopted for the fusion calculus.
For the entire collection see [Zbl 0893.00039].