Vertex cover might be hard to approximate to within 2-ε
Subhash Khot, Oded Regev · 2004
Based on a conjecture regarding the power of unique 2-prover-1-round games presented in [S. Khot, (2002)], 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 than k.