Symmetries of Symmetry Breaking Constraints
Abstract
Symmetry is an important feature of many constraint programs. We show that any symmetry acting on a set of symmetry breaking constraints can be used to break symmetry. Different symmetries pick out different solutions in each symmetry class. We use these observations in two methods for eliminating symmetry from a problem. These methods are designed to have many of the advantages of symmetry breaking methods that post static symmetry breaking constraint without some of the disadvantages. In particular, the two methods prune the search space using fast and efficient propagation of posted constraints, whilst reducing the conflict between symmetry breaking and branching heuristics. Experimental results show that the two methods perform well on some standard benchmarks.
Keywords
Cite
@article{arxiv.0909.3276,
title = {Symmetries of Symmetry Breaking Constraints},
author = {George Katsirelos and Toby Walsh},
journal= {arXiv preprint arXiv:0909.3276},
year = {2009}
}
Comments
To appear in the Proceedings of the Ninth International Workshop on Symmetry and Constraint Satisfaction Problems, held alongside the 15th International Conference on Principles and Practice of Constraint Programming (CP 2009), Lisbon, Portugal