Faster Exact Solving of SAT Formulae with a Low Number of Occurrences per Variable

  • Magnus Wahlström
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3569)


We present an algorithm that decides the satisfiability of a formula F on CNF form in time O(1.1279(d − 2)n), if F has at most d occurrences per variable or if F has an average of d occurrences per variable and no variable occurs only once. For d ≤ 4, this is better than previous results. This is the first published algorithm that is explicitly constructed to be efficient for cases with a low number of occurrences per variable. Previous algorithms that are applicable to this case exist, but as these are designed for other (more general, or simply different) cases, their performance guarantees for this case are weaker.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Magnus Wahlström
    • 1
  1. 1.Department of Computer and Information ScienceLinköping UniversityLinköpingSweden

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