A Class of f -consistencies for Qualitative Constraint Networks

In this paper, we introduce a new class of local consistencies, called f -consistencies, for qualitative constraint networks. Each consistency of this class is based on weak composition ( ) and a mapping f that provides a covering for each relation. We study the connections existing between some properties of mappings f and the relative inference strength of f -consistencies. The consistency obtained by the usual closure under weak composition is shown to be the weakest element of the class, and new promising perspectives are shown to be opened by f -consistencies stronger than weak composition. We also propose a generic algorithm that allows us to compute the closure of qualitative constraint networks under any “well-behaved” consistency of the class. The experimentation that we have conducted on qualitative constraint networks from the Interval Algebra shows the interest of these new local consistencies, in particular for the consistency problem.