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A note on Erdős-Diophantine graphs and Diophantine carpets

Axel Kohnert·Sascha Kurz
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Abstract

A Diophantine figure is a set of points on the integer grid $\mathbb{Z}^{2}$ where all mutual Euclidean distances are integers. We also speak of Diophantine graphs. In this language a Diophantine figure is a complete Diophantine graph. Due to a famous theorem of Erdős and Anning there are complete Diophantine graphs which are not contained in larger ones. We call them Erdős-Diophantine graphs. A special class of Diophantine graphs are Diophantine carpets. These are planar triangulations of a subset of the integer grid. We give an effective construction for Erdős-Diophantine graphs and characterize the chromatic number of Diophantine carpets.

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Axel Kohnert, Sascha Kurz. 2005-11-29. A note on Erdős-Diophantine graphs and Diophantine carpets. https://arxiv.org/abs/math/0511705

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