Claims

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1987_09_01_nesetril_rodl: For every n, Nešetřil and Rödl (1987) give a C_4-free graph whose n-colored edges always carry a monochromatic C_6, while by Erdős and Hajnal (1967) every C_4-free graph is a countable union of trees, so (C_4, C_6) qualifies.

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