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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 statement10 of 13

The smallest case not on this page is k=9k=9: But that one can be solved as well: The chromatic number of J(18,9)J(18, 9) is at least 1111.

FormalConjectures/ErdosProblems/835.leanErdos835.johnsonGraph_18_9_chromaticNumber1 lineExact file
(SimpleGraph.johnson 18 9).chromaticNumber > 9 + 1
SolvedStatement only, no proof