Abstract
An effective SAT preprocessing technique is the addition of symmetry-breaking predicates: auxiliary clauses that guide a SAT solver away from needless exploration of isomorphic sub-problems. Symmetry-breaking predicates have been in use for over a decade. However, it was not known how to express the addition of these predicates in proofs of unsatisfiability. Hence, results obtained by symmetry breaking cannot be validated by existing proof checkers. We present a method to express the addition of symmetry-breaking predicates in DRAT, a clausal proof format supported by top-tier solvers. We applied this method to generate SAT problems that have not been previously solved without symmetry-breaking predicates. We validated these proofs with an ACL2-based, mechanically-verified DRAT proof checker and the proof-checking tool of SAT Competition 2014.
The authors are supported by DARPA contract number N66001-10-2-4087.
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- 1.
available at http://www.cs.utexas.edu/~marijn/drat-trim/.
- 2.
available at http://www.cs.utexas.edu/~marijn/sbp/.
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Heule, M.J.H., Hunt, W.A., Wetzler, N. (2015). Expressing Symmetry Breaking in DRAT Proofs. In: Felty, A., Middeldorp, A. (eds) Automated Deduction - CADE-25. CADE 2015. Lecture Notes in Computer Science(), vol 9195. Springer, Cham. https://doi.org/10.1007/978-3-319-21401-6_40
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