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Tractable disjunctive constraints

  • David Cohen
  • Peter Jeavons
  • Manolis Koubarakis
Session 7a
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1330)

Abstract

Many combinatorial search problems can be expressed as ‘constraint satisfaction problems’, and this class of problems is known to be NP-complete in general. In this paper we investigate ‘disjunctive constraints’, that is, constraints which have the form of the disjunction of two constraints of specified types. We show that when the constraint types involved in the disjunction have a certain property, which we call ‘independence’, and when a certain restricted class of problems is tractable, then the class of all problems involving these disjunctive constraints is tractable. We give examples to show that many known examples of tractable constraint classes arise in this way, and derive new tractable classes which have not previously been identified.

Keywords

Constraint satisfaction problem complexity NP-completeness 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • David Cohen
    • 1
  • Peter Jeavons
    • 1
  • Manolis Koubarakis
    • 2
  1. 1.Department of Computer Science, Royal HollowayUniversity of LondonUK
  2. 2.Department of ComputationUMISTManchesterUK

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