A note on hardness of promise hypergraph colouring
We show a slightly simpler proof the following theorem by I. Dinur, O. Regev, and C. Smyth: for all c ≥ 2, it is NP-hard to find a c-colouring of a 2-coloruable 3-uniform hypergraph. We recast this result in the algebraic framework for Promise CSPs, using only a weaker version of the PCP theorem.
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