Watched Literals for Constraint Propagation in Minion

  • Ian P. Gent
  • Chris Jefferson
  • Ian Miguel
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4204)


Efficient constraint propagation is crucial to any constraint solver. We show that watched literals, already a great success in the satisfiability community, can be used to provide highly efficient implementations of constraint propagators. We describe three important aspects of watched literals as we apply them to constraints, and how they are implemented in the Minion constraint solver. We show three successful applications of to constraint propagators: the sum of Boolean variables; GAC for the ‘element’ constraint; and GAC for the ‘table’ constraint.


Constraint Propagation Constraint Solver Table Constraint Propagation Guarantee Element Constraint 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Ian P. Gent
    • 1
  • Chris Jefferson
    • 2
  • Ian Miguel
    • 1
  1. 1.School of Computer ScienceUniversity of St AndrewsSt AndrewsUK
  2. 2.Oxford University Computing LaboratoryUniversity of OxfordOxfordUK

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