The complexity of homomorphisms and renamings for minimal unsatisfiable formulas |
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Authors: | Hans Kleine Büning Daoyun Xu |
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Affiliation: | (1) Department of Computer Science, Universität Paderborn, 33095 Paderborn, Germany |
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Abstract: | We investigate the complexity of deciding whether for minimal unsatisfiable formulas F and H there exists a variable renaming, a literal renaming or a homomorphism such that (F)=H. A variable renaming is a permutation of variables. A literal renaming is a permutation of variables which additionally replaces some of the variables by its complements. A homomorphism can be considered as a literal renaming which can map different literals to one literal. |
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Keywords: | complexity renaming homomorphism minimal unsatisfiable formula graph isomorphism |
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