Constraint Solving by Martine Ceberio

Classical constraint programming systems are helpless when the constraints system to solve has no solution. Most of the times, only a “no solution” message is provided. The user is left alone to find out why there was no solution: is it because of the problem itself (no solution exists)? a bad modeling? a bug in the solver? etc.

In such a situation, soft constraints can help (see our tutorial on soft constraints). However, to better understand the situation and possibly resolve it, it might help to know which subset of the original set of constraints led to the unexpected situation.

Explanations constitute a promising way for providing such an information, where an explanation is a set of constraints that justify an action of the solver (value removal, bound update, contradiction).

Some of the people involved in e-programming are:

  • Baudel, Thomas
  • Benoist, Thierry
  • Boizumault, Patrice
    • Email: Patrice.Boizumault /
    • Website: Not available
    • Research: Constraint solving, Constraint Programming
  • Boucard, Didier
  • Buscaylet, Fabrice
    • Email: fabrice.buscaylet /
    • Website: Not available
    • Research: Constraint programming in general, optimization , hybridation.
  • Chun, Andy
  • Creemers, Tom
    • Email: creemers /
    • Website:
    • Research: Constraint Programming, Constraint Logic Programming, Explanation-based CP, Interval Methods, Multi-agent Constraint Systems
  • Debruyne, Romuald
  • DECHAMP, Luc
  • Deransart, Pierre
  • Djerourou, Faycal
    • Email: faycal.djerourou /
    • Website:
    • Research: Constraint programming Resolution of VCSP with metaheuristics
  • Douence, Rémi
    • Email: douence /
    • Website:
    • Research: Functional Languages, Software Architecture Languages. Object-Oriented Reflexive Languages Static and Dynamic Analysis (Debugging, Profiling). Aspect-Oriented Programming. Component-based Programming. And constraints.
  • Ed-Dbali, AbdelAli
    • Email: AbdelAli.ed-dbali /
    • Website:
    • Research: Therotical aspects on constraint programming explanations and their use for debugging; and uses of Explanations for dynamic scheduling problems
  • El Hadj, El Meddah
    • Email: h_meddah /
    • Website: Not available
    • Research: Not available
  • Ferrand, Gérard
  • Georget, Yan
  • Guéhéneuc, Yann-Gaël
    • Email: yann-gael /
    • Website:
    • Research: Software engineering and reengineering; Automated detection and correction of design defects, using explanation-based constraint programming.