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  • 标题:Improved inapproximability factors for some 2p minimization problems
  • 本地全文:下载
  • 作者:Kevin Dick ; Chris Umans
  • 期刊名称:Electronic Colloquium on Computational Complexity
  • 印刷版ISSN:1433-8092
  • 出版年度:2009
  • 卷号:2009
  • 出版社:Universität Trier, Lehrstuhl für Theoretische Computer-Forschung
  • 摘要:

    We give improved inapproximability results for some minimization problems in the second level of the Polynomial-Time Hierarchy. Extending previous work by Umans [Uma99], we show that several variants of DNF minimization are p2-hard to approximate to within factors of n13− and n12− (where the previous results achieved n14− ), for arbitrarily small constant 0">0. For one problem shown to be inapproximable to within n12− , we give a matching O(n12) -approximation algorithm, running in randomized polynomial time with access to an NP oracle, which shows that this result is tight assuming the PH doesn't collapse.

  • 关键词:DNF minimization; Inapproximability; polynomial hierarchy
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