A Unified Proof System for QBF Preprocessing [chapter]

Marijn J. H. Heule, Martina Seidl, Armin Biere
2014 Lecture Notes in Computer Science  
For quantified Boolean formulas (QBFs), preprocessing is essential to solve many real-world formulas. Application of a preprocessor, however, prevented the extraction of proofs to independently validate correctness of the solver's result. Especially for universal expansion proof checking was not possible so far. In this paper, we introduce a unified proof system based on three simple and elegant quantified asymmetric tautology (QRAT) rules. In combination with an extended version of universal
more » ... duction, they are sufficient to efficiently express all preprocessing techniques used in state-of-the-art preprocessors including universal expansion. Moreover, these rules give rise to new preprocessing techniques. We equip our preprocessor bloqqer with QRAT proof logging and provide a proof checker for QRAT proofs.
doi:10.1007/978-3-319-08587-6_7 fatcat:ew3o4nk5j5f2dktgx3avwvnw3e