Domain Independent Propagation

Recent years have seen the emergence of two main approaches to integrating constraints into logic programming. The CLP Scheme introduces constraints as basic statements over built-in computation domains. On the other hand, systems such as CHIP have introduced new inference rules, which enable certain predicates to be used for propagation thereby pruning the search tree. Unfortunately these two complementary approaches were up to now incompatible, since propagation techniques appeared intimately tied to the notion of nite domains. This paper introduces a general-isation of propagation that is applicable to any CLP computation domain, thereby restoring or-thogonality and bridging the gap between two important constraint logic programming paradigms. The practical interest of this new notion of \do-main independent" propagation is demonstrated by applying a prototype system for solving some hard search problems.