Eligible and frozen constraints for solving temporal qualitative constraint networks

Abstract

In this paper we consider the consistency problem for qualitative constraint networks representing temporal or spatial information. The most efficient method for solving this problem consists in a search algorithm using, on the one hand, the weak composition closure method as a local propagation method, and on the other hand, a decomposition of the constraints into subrelations of a tractable set. We extend this algorithm with the notion of eligibility and the notion of frozen constraints. The first concept allows to characterise constraints which will not be considered during the search. The second one allows to freeze constraints in order to avoid unnecessary updates. © Springer-Verlag Berlin Heidelberg 2007.