Binary Representations for General CSPs

It is well known that a non-binary constraint satisfaction problem (CSP) can be transformed into an equivalent binary CSP using the dual graph transformation. It is also known that the dual graph transformation is impractical in some cases where the CSP has a large number of constraints and/or the constraints have a larger number of satisfying tuples. However, little work has been done on improving transformation methods. In this paper, we introduce a constraint representative graph called w-graph and present a new transformation methods based on the w-graph. We show that the w-graph based transformation is a generalization of the dual graph tra~asformation and it overcomes certain weaknesses of the dual graph transformation in many cases.