Forum of Mathematics, Sigma (Jan 2021)

All finite sets are Ramsey in the maximum norm

  • Andrey Kupavskii,
  • Arsenii Sagdeev

DOI
https://doi.org/10.1017/fms.2021.50
Journal volume & issue
Vol. 9

Abstract

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For two metric spaces $\mathbb X$ and $\mathcal Y$ the chromatic number $\chi ({{\mathbb X}};{{\mathcal{Y}}})$ of $\mathbb X$ with forbidden $\mathcal Y$ is the smallest k such that there is a colouring of the points of $\mathbb X$ with k colors that contains no monochromatic copy of $\mathcal Y$. In this article, we show that for each finite metric space $\mathcal {M}$ that contains at least two points the value $\chi \left ({{\mathbb R}}^n_\infty; \mathcal M \right )$ grows exponentially with n. We also provide explicit lower and upper bounds for some special $\mathcal M$.

Keywords