Eriksson, L., Lagerkvist, V., Ordyniak, S. orcid.org/0000-0003-1935-651X et al. (3 more authors) (2024) Solving Quantified Boolean Formulas with Few Existential Variables. In: Proceedings of the Thirty-Third International Joint Conference on Artificial Intelligence. IJCAI 2024, 03-09 Aug 2024, Jeju Island, South Korea. IJCAI , California, USA , pp. 1889-1897. ISBN 978-1-956792-04-1
Abstract
The quantified Boolean formula (QBF) problem is an important decision problem generally viewed as the archetype for PSPACE-completeness. Many problems of central interest in AI are in general not included in NP, e.g., planning, model checking, and non-monotonic reasoning, and for such problems QBF has successfully been used as a modelling tool. However, solvers for QBF are not as advanced as state of the art SAT solvers, which has prevented QBF from becoming a universal modelling language for PSPACE-complete problems. A theoretical explanation is that QBF (as well as many other PSPACE-complete problems) lacks natural parameters guaranteeing fixed-parameter tractability (FPT). In this paper we tackle this problem and consider a simple but overlooked parameter: the number of existentially quantified variables. This natural parameter is virtually unexplored in the literature which one might find surprising given the general scarcity of FPT algorithms for QBF. Via this parameterization we then develop a novel FPT algorithm applicable to QBF instances in conjunctive normal form (CNF) of bounded clause length. We complement this by a W[1]-hardness result for QBF in CNF of unbounded clause length as well as sharper lower bounds for the bounded arity case under the (strong) exponential-time hypothesis.
Metadata
Item Type: | Proceedings Paper |
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Authors/Creators: |
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Keywords: | Satisfiability, Constraint satisfaction, Computational complexity of reasoning |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Computing (Leeds) > Algorithms & Complexity |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/V00252X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 May 2024 12:16 |
Last Modified: | 06 Aug 2024 07:44 |
Published Version: | https://www.ijcai.org/proceedings/2024/209 |
Status: | Published |
Publisher: | IJCAI |
Identification Number: | 10.24963/ijcai.2024/209 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:212223 |