Symmetry and consistency

Abstract

We introduce a novel and exciting research area: symmetrising levels of consistency to produce stronger forms of consistency and more efficient mechanisms for establishing them. We propose new levels of consistency for Constraint Satisfaction Problems (CSPs) incorporating the symmetry group of a CSP. We first define Sym(i, j)-consistency, show that even Sym(1,0)-consistency can prune usefully, and study some consequences of maintaining Sym(i, 0)-consistency. Weconsistency then present pseudocode for SymPath consistency, and a symmetrised version of singleton consistency, before presenting experimental evidence of these algorithms' practical effectiveness. With this contribution we establish the study of symmetry-based levels of consistency of CSPs. © Springer-Verlag Berlin Heidelberg 2005.