Journal of Heuristics

, Volume 12, Issue 4–5, pp 263–285 | Cite as

Hard and soft constraints for reasoning about qualitative conditional preferences

  • C. Domshlak
  • S. Prestwich
  • F. Rossi
  • K. B. VenableEmail author
  • T. Walsh


Many real life optimization problems are defined in terms of both hard and soft constraints, and qualitative conditional preferences. However, there is as yet no single framework for combined reasoning about these three kinds of information. In this paper we study how to exploit classical and soft constraint solvers for handling qualitative preference statements such as those captured by the CP-nets model. In particular, we show how hard constraints are sufficient to model the optimal outcomes of a possibly cyclic CP-net, and how soft constraints can faithfully approximate the semantics of acyclic conditional preference statements whilst improving the computational efficiency of reasoning about these statements.


Preferences Hard and Soft Constraints CP-nets 


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Copyright information

© Springer Science + Business Media, LLC 2006

Authors and Affiliations

  • C. Domshlak
    • 1
  • S. Prestwich
    • 2
  • F. Rossi
    • 3
  • K. B. Venable
    • 3
    Email author
  • T. Walsh
    • 4
  1. 1.William Davidson Faculty of Industrial Engineering and ManagementTechnion—Israel Institute of TechnologyTechnion City, HaifaIsrael
  2. 2.Department of Computer ScienceUniversity College CorkCorkIreland
  3. 3.Department of MathematicsUniversity of PadovaPadovaItaly
  4. 4.National ICT Australia and School of Computer Science and EngineeringUniversity of New South WalesSydneyAustralia

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