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Erdős problem 835

Does there exist a k>2k>2 such that the kk-sized subsets of {1,...,2k} can be coloured with k+1k+1 colours such that for every A⊂{1,…,2k}A\subset \{1,\ldots,2k\} with ∣A∣=k+1\lvert A\rvert=k+1 all k+1k+1 colours appear among the kk-sized subsets of AA?

Sources

The source's own material, retained exactly.

13 retained statements36c6d0fef71a

Open selected source

FormalConjectures/ErdosProblems/

835.lean

Retained formal statement3 of 13

Johnson's bound for the chromatic number of the Johnson graph.

FormalConjectures/ErdosProblems/835.leanErdos835.div_johnsonBound_le_chromaticNum_johnson1 lineExact file
∀ {n k : ℕ}, ↑⌈↑(n.choose k) / ↑(Erdos835.johnsonBound n 4 k)⌉₊ ≤ (SimpleGraph.johnson n k).chromaticNumber
SolvedStatement only, no proof