Abstract. Subquadrangles are a natural way in which to represent constraints as they do not restrict any subset of their scope. There are already known methods for converting any given constraint into a set of subquadrangles, but we require a method by which an entire constraint satisfaction problem instance can be converted as a whole. In this paper we present two methods by which we might decompose a given instance into a solution equivalent instance whose constraints are all subquadrangles.
Chris Houghton, David A. Cohen