The Essence of Constraint Propagation

We show that several constraint propagation algorithms (also called (local) consistency, consistency enforcing, Waltz, filtering or narrowing algorithms) are instances of algorithms that deal with chaotic iteration. To this end we propose a simple abstract framework that allows us to classify and compare these algorithms and to establish in a uniform way their basic properties. Note. This is a full, revised version of our article “From Chaotic Iteration to Constraint Propagation”, Proc. of 24th International Colloquium on Automata, Languages and Programming (ICALP ’97), (invited lecture), Springer-Verlag Lecture Notes in Computer Science 1256, pp. 3655, (1997).