Learn More
A 2-prover game is called unique if the answer of one prover uniquely determines the answer of the second prover and vice versa (we implicitly assume games to be one round games). The value of a 2-prover game is the maximum acceptance probability of the verifier over all the prover strategies. We make the following conjecture regarding the power of unique(More)
Based on a conjecture regarding the power of unique 2-prover-1-round games presented in [Khot02], we show that vertex cover is hard to approximate within any constant factor better than 2. We actually show a stronger result, namely, based on the same conjecture, vertex cover on k-uniform hypergraphs is hard to approximate within any constant factor better(More)
In this paper, we give evidence suggesting that MAX-CUT is NP-hard to approximate to within a factor of /spl alpha//sub cw/+ /spl epsi/, for all /spl epsi/ > 0, where /spl alpha//sub cw/ denotes the approximation ratio achieved by the Goemans-Williamson algorithm (1995). /spl alpha//sub cw/ /spl ap/ .878567. This result is conditional, relying on two(More)
  • Subhash Khot
  • 45th Annual IEEE Symposium on Foundations of…
  • 2004
Assuming that NP /spl nsube//spl cap//sub /spl epsi/> 0/ BPTIME(2/sup n/spl epsi//), we show that graph min-bisection, densest subgraph and bipartite clique have no PTAS. We give a reduction from the minimum distance of code problem (MDC). Starting with an instance of MDC, we build a quasi-random PCP that suffices to prove the desired inapproximability(More)
In this article, we disprove a conjecture of Goemans and Linial; namely, that every negative type metric embeds into &ell;<sub>1</sub> with constant distortion. We show that for an arbitrarily small constant &#916; &gt; 0, for all large enough <i>n</i>, there is an <i>n</i>-point negative type metric which requires distortion at least (log log(More)
We study the communication complexity of the set disjointness problem in the general multi-party model. For t players, each holding a subset of a universe of size n, we establish a near-optimal lower bound of Ω(n/(t log t)) on the communication complexity of the problem of determining whether their sets are disjoint. In the more restrictive one-way(More)
Given a <i>k</i>-uniform hyper-graph, the E<i>k</i>-Vertex-Cover problem is to find the smallest subset of vertices that intersects every hyper-edge. We present a new multilayered PCP construction that extends the Raz verifier. This enables us to prove that E<i>k</i>-Vertex-Cover is NP-hard to approximate within factor <i>(k-1-&#949;)</i> for any <i>k(More)
Various new nonembeddability results (mainly into L/sub 1/) are proved via Fourier analysis. In particular, it is shown that the edit distance on {0, 1}/sup d/ has L/sub 1/ distortion (log d)/sup 1/2 - o(1)/. We also give new lower bounds on the L/sub 1/ distortion of quotients of the discrete hypercube under group actions, and the transportation cost(More)
For arbitrarily small constants epsilon, delta &#x226B; 0$, we present a long code test with one free bit, completeness 1-epsilon and soundness delta. Using the test, we prove the following two inapproximability results:1. Assuming the Unique Games Conjecture of Khot, given an n-vertex graph that has two disjoint independent sets of size (1/2-epsilon)n(More)
For every integer k > 0, and an arbitrarily small constant ε > 0, we present a PCP characterization of NP where the verifier uses logarithmic randomness, non-adaptively queries 4k + k2 bits in the proof, accepts a correct proof with probability 1, i. e., it has perfect completeness, and accepts any supposed proof of a false statement with probability at(More)