A substitution operation for constraints

  • Peter Jeavons
  • David Cohen
  • Martin Cooper
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 874)


In order to reduce the search space in finite constraint satisfaction problems, a number of different preprocessing schemes have been proposed. This paper introduces a ‘substitution’ operation for constraints. This new operation generalizes both the idea of enforcing consistency and the notion of label substitution introduced by Freuder. We show that the constraints in a problem may be replaced by substitutable subsets in order to simplify the problem without affecting the existence of a solution. Furthermore, we show how substitutability may be established locally, by considering only a subproblem of the complete problem.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1994

Authors and Affiliations

  • Peter Jeavons
    • 1
  • David Cohen
    • 1
  • Martin Cooper
    • 2
  1. 1.Department of Computer ScienceRoyal Holloway, University of LondonUK
  2. 2.IRITUniversity of Toulouse IIIFrance

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