Sir Timothy Gowers (Fields Medallist and Mathematics Professor) talks about Van der Waerden's theorem, which belongs to the mathematical topic Ramsey theory.
Colouring Numbers - Numberphile
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Jan 21, 2020
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Numberphile2
Jan 22, 2020
WP: Timothy Gowers
WP: Van der Waerden's theorem
WP: Ramsey theory