Title
Conditional Hardness for Approximate Coloring.
Abstract
We study the APRXCOLORING(q, Q) problem: Given a graph G, decide whether chi(G) <= q or chi(G) >= Q. We present hardness results for this problem for any constants 3 <= q < Q. For q >= 4, our result is based on Khot's 2-to-1 label cover, which is conjectured to be NP-hard [S. Khot, Proceedings of the 34th Annual ACM Symposium on Theory of Computing, 2002, pp. 767-775]. For q = 3, we base our hardness result on a certain "x-shaped" variant of his conjecture. Previously no hardness result was known for q = 3 and Q >= 6. At the heart of our proof are tight bounds on generalized noise-stability quantities, which extend the recent work of Mossel, O'Donnell, and Oleszkiewicz ["Noise stability of functions with low influences: Invariance and optimality," Ann. of Math. (2), to appear] and should have wider applicability.
Year
DOI
Venue
2009
10.1137/07068062X
SIAM JOURNAL ON COMPUTING
Keywords
DocType
Volume
hardness of approximation,unique games,graph coloring
Journal
39
Issue
ISSN
Citations 
3
0097-5397
3
PageRank 
References 
Authors
0.40
0
3
Name
Order
Citations
PageRank
Irit Dinur1118785.67
Elchanan Mossel21725145.16
Oded Regev32322133.33