On the Lovász Theta function for independent sets in sparse graphs

Nikhil Bansal, Anupam Gupta, Guru Guruganesh

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We consider the maximum independent set problem on sparse graphs with maximum degree d. We show that the integrality gap of the Lovász θ-function based SDP has an integrality gap of Õ(d/log3/2d). This improves on the previous best result of Õ (d/log d), and narrows the gap of this basic SDP to the integrality gap of Õ(d/log2 d) recently shown for stronger SDPs, namely those obtained using poly log (d) levels of the SA+ semidefinite hierarchy. The improvement comes from an improved Ramsey-theoretic bound on the independence number of Kr- free graphs for large values of r. We also show how to obtain an algorithmic version of the above-mentioned SA -based integrality gap result, via a coloring algorithm of Johansson. The resulting approximation guarantee of Õ (d/log2 d) matches the best unique-games-based hardness result up to lower-order poly (log log d) factors.

Original languageEnglish (US)
Title of host publicationSTOC 2015 - Proceedings of the 2015 ACM Symposium on Theory of Computing
PublisherAssociation for Computing Machinery
Pages193-200
Number of pages8
ISBN (Electronic)9781450335362
DOIs
StatePublished - Jun 14 2015
Event47th Annual ACM Symposium on Theory of Computing, STOC 2015 - Portland, United States
Duration: Jun 14 2015Jun 17 2015

Publication series

NameProceedings of the Annual ACM Symposium on Theory of Computing
Volume14-17-June-2015
ISSN (Print)0737-8017

Other

Other47th Annual ACM Symposium on Theory of Computing, STOC 2015
Country/TerritoryUnited States
CityPortland
Period6/14/156/17/15

ASJC Scopus subject areas

  • Software

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