Combined Strategies for Decomposition-based Methods for solving CSPs
Résumé
In this paper, we consider theoretical and practical methods based on decompositions of constraint networks. We exploit the fact that decomposition-based methods can be used considering two steps. The first step is related to the
(hyper)graphical decomposition (e.g. Tree-Decomposition [Robertson and Seymour, 1986] or Hypertree-Decomposition [Gottlob, Leone and Scarcello, 2000]) while the second step exploits the decomposition to solve the CSPs. Thanks to this approach, we define then hybrid methods which can be optimal from a theoretical viewpoint while being efficient in practice. The complexity analysis of these combined methods allows us to give a more detailed presentation of the Constraint Tractability Hierarchy introduced in [Gottlob, Leone and Scarcello, 2000]. Finally, we justify our approach with experimental results.