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Questions about the hardest problems in NP, i.e. of those that can be solved in polynomial time by nondeterministic Turing machines.

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Let's introduce a variable $x_i$ for every node $i$, representing the condition that the node is part of the vertex cover. Then for every edge $\{v,w\}$ we introduce the clause $x_v \lor x_w$. We hav …
answered Mar 9 '14 by Niklas B.