Integrating Finite Domain and Set Constraints into a Set-based Constraint Language

This paper summarizes a constraint solving technique that is used to reason effectively in the scope of a set-based constraint language that supersedes existing finite domain languages. The first part of this paper motivates the presented work and introduces the constraint language, namely the language of Hereditarily Finite Sets (HFS). Then, the proposed constraint solver is detailed in terms of a set of rewrite rules that exploit finite domain reasoning within the HFS language. The proposed solution improves previous work on CLP(SET) by integrating intervals into the constraint system and by providing a new layered architecture for the solver that supports more effective constraint solving strategies. On the other hand, the proposed approach provides enhanced expressivity and flexibility of domain representation than those usually found in existing finite domain constraint solvers.