On the hardness of approximating label-cover
The Label-Cover problem, defined by S. Arora, L. Babai, J. Stern, Z. Sweedyk [Proceedings of 34th IEEE Symposium on Foundations of Computer Science, 1993, pp. 724–733], serves as a starting point for numerous hardness of approximation reductions. It is one of six ‘canonical’ approximation problems i...
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| Vydáno v: | Information processing letters Ročník 89; číslo 5; s. 247 - 254 |
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| Hlavní autoři: | , |
| Médium: | Journal Article |
| Jazyk: | angličtina |
| Vydáno: |
Amsterdam
Elsevier B.V
16.03.2004
Elsevier Science Elsevier Sequoia S.A |
| Témata: | |
| ISSN: | 0020-0190, 1872-6119 |
| On-line přístup: | Získat plný text |
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| Shrnutí: | The
Label-Cover problem, defined by S. Arora, L. Babai, J. Stern, Z. Sweedyk [Proceedings of 34th IEEE Symposium on Foundations of Computer Science, 1993, pp. 724–733], serves as a starting point for numerous hardness of approximation reductions. It is one of six ‘canonical’ approximation problems in the survey of Arora and Lund [Hardness of Approximations, in: Approximation Algorithms for NP-Hard Problems, PWS Publishing Company, 1996, Chapter 10]. In this paper we present a direct combinatorial reduction from low error-probability PCP [Proceedings of 31st ACM Symposium on Theory of Computing, 1999, pp. 29–40] to
Label-Cover showing it NP-hard to approximate to within 2
(log
n)
1−o(1)
. This improves upon the best previous hardness of approximation results known for this problem.
We also consider the
Minimum-Monotone-Satisfying-Assignment (MMSA) problem of finding a satisfying assignment to a monotone formula with the least number of 1's, introduced by M. Alekhnovich, S. Buss, S. Moran, T. Pitassi [Minimum propositional proof length is NP-hard to linearly approximate, 1998]. We define a hierarchy of approximation problems obtained by restricting the number of alternations of the monotone formula. This hierarchy turns out to be equivalent to an AND/OR scheduling hierarchy suggested by M.H. Goldwasser, R. Motwani [Lecture Notes in Comput. Sci., Vol. 1272, Springer-Verlag, 1997, pp. 307–320]. We show some hardness results for certain levels in this hierarchy, and place
Label-Cover between levels 3 and 4. This partially answers an open problem from M.H. Goldwasser, R. Motwani regarding the precise complexity of each level in the hierarchy, and the place of
Label-Cover in it. |
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| Bibliografie: | SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 14 |
| ISSN: | 0020-0190 1872-6119 |
| DOI: | 10.1016/j.ipl.2003.11.007 |