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An Improvement of the Algorithm of Hertli for the Unique 3SAT Problem

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Part of the book series: Lecture Notes in Computer Science ((LNTCS,volume 10755))

Abstract

We propose a simple idea for improving the randomized algorithm of Hertli for the Unique 3SAT problem. Using recently developed techniques, we can derive from this algorithm the currently the fastest randomized algorithm for the general 3SAT problem.

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Notes

  1. 1.

    Throughout this paper, we use n, the number of variables of an input formula, as a size parameter. Following the standard convention on this topic, we ignore the polynomial factor for discussing the time complexity of algorithms, and by \({\widetilde{O}}(T(n))\) we denote O(T(n)p(n)) for some polynomial p.

  2. 2.

    In [2], the part of the algorithm \(\mathrm{HERTLI}\) corresponding to the statements 5–16 of Algorithm 2 is stated as algorithm OneCC (i.e., Algorithm 3 in [2]). On the other hand, we omit specifying it here and include it in Algorithm 2. In order to use algorithm numbering consistent with [2], we skip Algorithm 3 here and state \(\mathrm{GetInd2Clauses}\) as Algorithm 4. While \(\mathrm{DensePPSZ}_p\) and \(\mathrm{SparsePPSZ}\) correspond to procedures Dense (Algorithm 5) and Sparse (Algorithm 6) of [2], we modify their descriptions for the sake of our later explanation. As a whole, the procedure \(\mathrm{HERTLI}\) is essentially the same as Hertli’s algorithm stated in [2].

  3. 3.

    Due to some minor error in [2], the choice of parameters in [2] is not appropriate, which has been corrected in [3]. Here we use this corrected version.

References

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  3. Hertli, T.: Improved exponential algorithms for SAT and ClSP. A thesis for Doctor of Sciences of ETH Zurich (2015)

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  8. Wahlström, M.: An algorithm for the SAT problem for formulae of linear length. In: Brodal, G.S., Leonardi, S. (eds.) ESA 2005. LNCS, vol. 3669, pp. 107–118. Springer, Heidelberg (2005). https://doi.org/10.1007/11561071_12

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Correspondence to Tong Qin .

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Qin, T., Watanabe, O. (2018). An Improvement of the Algorithm of Hertli for the Unique 3SAT Problem. In: Rahman, M., Sung, WK., Uehara, R. (eds) WALCOM: Algorithms and Computation. WALCOM 2018. Lecture Notes in Computer Science(), vol 10755. Springer, Cham. https://doi.org/10.1007/978-3-319-75172-6_9

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  • DOI: https://doi.org/10.1007/978-3-319-75172-6_9

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  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-75171-9

  • Online ISBN: 978-3-319-75172-6

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