Nearly all known Euclidean Ramsey sets are subsoluble
Combinatorics
2025-12-05 v3
Abstract
A finite set in a Euclidean space is called Ramsey if for every there exists an integer such that whenever is coloured with colours, there is a monochromatic copy of . Graham conjectured that all spherical sets are Ramsey, but progress on this conjecture has been slow. A key result of K\v{r}\'{i}\v{z} is that all sets that embed in sets that are acted on transitively by a soluble group are Ramsey. We show that for nearly all known examples of Ramsey sets the converse is true, with only two possible exceptions.
Cite
@article{arxiv.2510.15677,
title = {Nearly all known Euclidean Ramsey sets are subsoluble},
author = {Natalie Behague},
journal= {arXiv preprint arXiv:2510.15677},
year = {2025}
}
Comments
15 pages, 2 figures. Version 2: Replaced proof that simplices are subsoluble with citation for pre-existing proof by Karamanlis. Version 3: Corrected some minor errors and added Figure 3