On the number of pairwise touching cylinders in $\mathbb{R}^d$
Combinatorics
2026-01-01 v1
Abstract
John E. Littlewood posted the question {\em ``Is it possible in 3-space for seven infinite circular cylinders of unit radius each to touch all the others? Seven is the number suggested by counting constants.''} Boz\'oki, Lee, and R\'onyai constructed a configuration of 7 mutually touching unit cylinders. The best-known upper bounds show that at most 10 unit cylinders in can mutually touch. We consider this problem in higher dimensions, and obtain exponential (in ) upper bounds on the number of mutually touching cylinders in . Our method is fairly flexible, and it makes use of the fact that cylinder touching can be expressed as a combination of polynomial equalities and non-equalities.
Keywords
Cite
@article{arxiv.2512.24595,
title = {On the number of pairwise touching cylinders in $\mathbb{R}^d$},
author = {Jozsef Solymosi and Josh Zahl},
journal= {arXiv preprint arXiv:2512.24595},
year = {2026}
}