Project CORSA:
Constraint mOdelling, Reformulation, Solving, and Analysis

• STINT, the Swedish Foundation for International Cooperation in Research and Higher Education, under Institutional Grant number IG2001-67

• Department of Information Technology, Uppsala University, Uppsala, Sweden (ASTRA Research Group)
• Department of Computer Science, Brown University, Providence, Rhode Island, USA
• Faculty of Engineering and Natural Sciences, Sabancι University, Istanbul, Turkey (only during the academic year 2006/07)

Members (only seniors listed):

• Pierre Flener, Uppsala University, principal investigator
• Justin Pearson, Uppsala University
• Meinolf Sellmann, Brown University
• Pascal Van Hentenryck, Brown University, principal investigator
• Magnus Ågren, Uppsala University, PhD student
• Ugur Sezerman, Sabancι University

Actual topics of research:

• Symmetry breaking for models of constraint satisfaction problems
• Symmetry detection in models of constraint satisfaction problems

Main publications so far:

1. P. Flener, J. Pearson, and M. Sellmann.
   Static and dynamic structural symmetry breaking.
   Annals of Mathematics and Artificial Intelligence, forthcoming. (PDF) (Preprint)
2. P. Flener, J. Pearson, M. Sellmann, P. Van Hentenryck, and M. Ågren.
   Dynamic structural symmetry breaking for constraint satisfaction problems.
   Constraints 14(4):506-538, December 2009. (PDF) (Preprint) (omitted material in Technical Report 2007-032)
3. P. Flener and J. Pearson.
   Solving necklace constraint problems.
   Journal of Algorithms, 64(2-3):61-73, April-July 2009. (PDF)
4. P. Flener and J. Pearson.
   Solving necklace constraint problems.
   In: M. Ghallab (editor), Proceedings of ECAI'08, pages 520-524. IOS Press, 2008. (Preprint) (superseded by the Journal of Algorithms paper in 2009)
5. P. Flener, J. Pearson, L.G. Reyna, and O. Sivertsson.
   Design of financial CDO squared transactions using constraint programming.
   Constraints 12(2):179-205, April 2007. (PDF) (Preprint)
6. P. Flener, J. Pearson, M. Sellmann, P. Van Hentenryck, and M. Ågren.
   Efficient structural symmetry breaking for constraint satisfaction problems.
   In: I.P. Gent and S. Linton (editors), Proceedings of the International Symmetry Conference. 2007. (PDF)
7. P. Flener, J. Pearson, M. Sellmann, and P. Van Hentenryck.
   Static and dynamic structural symmetry breaking.
   In: F. Benhamou (editor), Proceedings of CP'06, the 12th international conference on Principles and Practice of Constraint Programming, pages 695-699.
   Lecture Notes in Computer Science, volume 4204. © Springer-Verlag, 2006. (PDF) (Preprint) (superseded by the Annals of Mathematics and Artificial Intelligence paper in 20xx)
8. D.S. Heller and M. Sellmann.
   Dynamic symmetry breaking restarted.
   In: F. Benhamou (editor), Proceedings of CP'06, the 12th international conference on Principles and Practice of Constraint Programming, pages 721-725.
   Lecture Notes in Computer Science, volume 4204. © Springer-Verlag, 2006. (Preprint)
9. M. Eriksson.
   Detecting Symmetries in Relational Models of CSPs.
   Master's Thesis in Computing Science, Department of Information Technology, Uppsala University, Sweden, November 2005. (PDF)
10. P. Van Hentenryck, P. Flener, J. Pearson, and M. Ågren.
    Compositional derivation of symmetries for constraint satisfaction.
    In: J.-D. Zucker and L. Saitta (editors), Proceedings of SARA'05, the 6th Symposium on Abstraction, Reformulation, and Approximation, pages 234-247.
    Lecture Notes in Artificial Intelligence, volume 3607. © Springer-Verlag, 2005. (PDF) (Preprint)
11. M. Sellmann and P. Van Hentenryck.
    Structural symmetry breaking.
    In Proceedings of IJCAI'05, the 19th International Joint Conference on Artificial Intelligence, pages 298-303.
    © IJCAI, 2005. (Preprint) (superseded by the Constraints paper in 2009)
12. P. Flener, J. Pearson, and L.G. Reyna.
    Financial portfolio optimisation.
    In: M. Wallace (editor), Proceedings of CP'04, the 10th international conference on Principles and Practice of Constraint Programming, pages 227-241.
    Lecture Notes in Computer Science, volume 3258. © Springer-Verlag, 2004. (PDF) (Preprint) (superseded by the Constraints paper in April 2007)
13. P. Van Hentenryck, P. Flener, J. Pearson, and M. Ågren.
    Tractable symmetry breaking for CSPs with interchangeable values.
    In Proceedings of IJCAI'03, the 18th International Joint Conference on Artificial Intelligence, pages 277-282.
    © Morgan Kaufmann Publishers, 2003. (Preprint) (superseded by the Constraints paper in 2009)

Other public activities so far:

• Launching of the SymCon series of International Workshops on Symmetry in Constraint Satisfaction Problems
• Chairing of SymCon01, SymCon02, SymCon05, and SymCon09, plus Programme Committee memberships for all other SymCon workshops so far
• Chairing of the invited special session Breaking Symmetries at the INFORMS Annual Meeting 2006