Procedural Reasoning in Constraint Satisfaction

For many constraint satisfaction problems, there are well known, fast algorithms and functions that solve parts of the problem. Using these methods directly to solve the sub-problems signiicantly speeds up the solving process. Unfortunately, doing this has usually required the solver to be changed, or the correctness criteria to be reexamined. We describe a general mechanism to use procedures with almost any search engine, such that it is easy to add any procedures without changing the engine. Furthermore, the framework is formally deened, which allows us to prove conditions that are suucient to guarantee systematicity and completeness for search engines using procedures.