On QBF Proofs and Preprocessing

  • Mikoláš Janota
  • Radu Grigore
  • Joao Marques-Silva
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8312)

Abstract

QBFs (quantified boolean formulas), which are a superset of propositional formulas, provide a canonical representation for PSPACE problems. To overcome the inherent complexity of QBF, significant effort has been invested in developing QBF solvers as well as the underlying proof systems. At the same time, formula preprocessing is crucial for the application of QBF solvers. This paper focuses on a missing link in currently-available technology: How to obtain a certificate (e.g. proof) for a formula that had been preprocessed before it was given to a solver? The paper targets a suite of commonly-used preprocessing techniques and shows how to reconstruct certificates for them. On the negative side, the paper discusses certain limitations of the currently-used proof systems in the light of preprocessing. The presented techniques were implemented and evaluated in the state-of-the-art QBF preprocessor bloqqer.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Mikoláš Janota
    • 1
  • Radu Grigore
    • 3
  • Joao Marques-Silva
    • 1
    • 2
  1. 1.INESC-IDLisbonPortugal
  2. 2.University College DublinIreland
  3. 3.University of OxfordUK

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