Abstract
˜Building on recent work that adapts failed-literal analysis (FL) to Quantified Boolean Formulas (QBF), this paper introduces extended failed-literal analysis (EFL). FL and EFL are both preprocessing methods that apply a fast, but incomplete reasoning procedure to abstractions of the underlying QBF. EFL extends FL by remembering certain binary clauses that are implied by the same reasoning procedure as FL when it assumes one literal and that implies a second literal. This extension is almost free because the second literals are implied anyway during FL, but compared to analogous techniques for propositional satisfiability, its correctness involves some subtleties. For the first time, application of the universal pure literal rule is considered without also applying the existential pure literal rule. It is shown that using both pure literal rules in EFL is unsound. A modified reasoning procedure for QBF, called Unit-clause Propagation with Universal Pure literals (UPUP) is described and correctness is proved for EFL based on UPUP. Empirical results on the 568-benchmark suite of QBFEVAL-10 are presented.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.