Rajsekar Manokaran Joseph Naor Prasad Raghavendra Roy Schwartz Sdp gaps and ugc hardness for multiway cut, 0-extension, and metric labeling. 11-20 2008 STOC http://doi.acm.org/10.1145/1374376.1374379 conf/stoc/2008 db/conf/stoc/stoc2008.html#ManokaranNRS08