Une contrainte globale pour le problème de l'isomorphisme de graphes

The graph isomorphism problem consists in deciding if two given graphs have an identical structure. This problem can be modeled as a constraint satisfaction problem in a very straightforward way, so that one can use constraint programming to solve it. However, constraint programming is a generic tool that may be less efficient than dedicated algorithms which can take advantage of the global semantic of the original problem. Hence, we introduce in this paper a new global constraint dedicated to graph isomorphism problems, and we define an associated filtering algorithm that exploits all edges of the graphs in a global way to narrow variable domains. We then show how this global constraint can be decomposed into a set of “distance” constraints which propagate more domain reductions than “edge” constraints that are usually generated for this problem. MOTS-CLÉS : Isomorphisme de graphes, contrainte globale