A Unified Proof System for QBF Preprocessing

  • Marijn J. H. Heule
  • Martina Seidl
  • Armin Biere
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8562)


For quantified Boolean formulas (QBFs), preprocessing is essential to solve many real-world formulas. The application of a preprocessor, however, prevented the extraction of proofs for the original formula. Such proofs are required to independently validate correctness of the preprocessor’s rewritings and 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 resolution asymmetric tautology (QRAT) rules. In combination with an extended version of universal reduction, 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.


Proof System Boolean Formula Preprocessing Technique Universal Expansion Empty Clause 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Marijn J. H. Heule
    • 1
  • Martina Seidl
    • 2
  • Armin Biere
    • 2
  1. 1.Department of Computer ScienceThe University of Texas at AustinUSA
  2. 2.Institute for Formal Models and VerificationJKU LinzAustria

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