Computer Science and Engineering, Department of
Date of this Version
2009
Abstract
Consistency properties and algorithms for achieving them are at the heart of the success of Constraint Programming. For non-binary Constraint Satisfaction Problems (CSPs), the relational-consistency property R(i,j)C of [Dechter and van Beek 1997] may add new non-binary constraints to the constraint network, thus modifying its topology. The domain-filtering properties of [Bessiere et al. 2008] filter the domains of the variables and leave the constraints unchanged but are restricted to combinations of two constraints. We restate the property of m-wise consistency [Gyssens 1986; Jegou 1993] as relational (*,m)-consistency, R(*,m)C. R(*,m)C ensures that any tuple in a relation is consistent in every combination of m constraints. The main contributions of this document are the design of an algorithm for enforcing R(∗,m)C and the evaluation of its effectiveness in a search procedure solving CSPs. This document thus establishes the usefulness in practice of higher consistency levels in non-binary CSPs.
Comments
Published in University of Nebraska–Lincoln, Computer Science and Engineering Technical Report TR-UNL-CSE-2009-0009 Issued June 23, 2009.