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An Improved Deterministic #SAT Algorithm for Small de Morgan Formulas

Published: 01 September 2016 Publication History

Abstract

We give a deterministic #SAT algorithm for de Morgan formulas of size up to $$n^{2.63}$$n2.63, which runs in time $$2^{n-n^{{\varOmega }(1)}}$$2n-nΩ(1). This improves upon the deterministic #SAT algorithm of Chen et al. (Proceedings of the twenty-ninth annual IEEE conference on computational complexity, 2014), which has similar running time but works only for formulas of size less than $$n^{2.5}$$n2.5. Our new algorithm is based on the shrinkage of de Morgan formulas under random restrictions, shown by Paterson and Zwick (Random Struct Algorithms 4(2):135---150, 1993). We prove a concentrated and constructive version of their shrinkage result. Namely, we give a deterministic polynomial-time algorithm that selects variables in a given de Morgan formula so that, with high probability over the random assignments to the chosen variables, the original formula shrinks in size, when simplified using a given deterministic polynomial-time formula-simplification algorithm.

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  1. An Improved Deterministic #SAT Algorithm for Small de Morgan Formulas

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    Published In

    cover image Algorithmica
    Algorithmica  Volume 76, Issue 1
    September 2016
    296 pages

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    Springer-Verlag

    Berlin, Heidelberg

    Publication History

    Published: 01 September 2016

    Author Tags

    1. Algorithms from circuit lower bounds
    2. Concentrated shrinkage
    3. Deterministic #SAT algorithms
    4. Random restrictions
    5. Shrinkage exponent
    6. de Morgan formulas

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