TY - GEN
T1 - On the Lovász Theta function for independent sets in sparse graphs
AU - Bansal, Nikhil
AU - Gupta, Anupam
AU - Guruganesh, Guru
N1 - Publisher Copyright:
© Copyright 2015 ACM.
PY - 2015/6/14
Y1 - 2015/6/14
N2 - 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.
AB - 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.
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U2 - 10.1145/2746539.2746607
DO - 10.1145/2746539.2746607
M3 - Conference contribution
AN - SCOPUS:84958777909
T3 - Proceedings of the Annual ACM Symposium on Theory of Computing
SP - 193
EP - 200
BT - STOC 2015 - Proceedings of the 2015 ACM Symposium on Theory of Computing
PB - Association for Computing Machinery
T2 - 47th Annual ACM Symposium on Theory of Computing, STOC 2015
Y2 - 14 June 2015 through 17 June 2015
ER -