English

Clustering in typical unit-distance avoiding sets

Metric Geometry 2024-07-09 v1 Combinatorics

Abstract

In the 1960s Moser asked how dense a subset of Rd\mathbb{R}^d can be if no pairs of points in the subset are exactly distance 1 apart. There has been a long line of work showing upper bounds on this density. One curious feature of dense unit distance avoiding sets is that they appear to be ``clumpy,'' i.e. forbidding unit distances comes hand in hand with having more than the expected number distance 2\approx 2 pairs. In this work we rigorously establish this phenomenon in R2\mathbb{R}^2. We show that dense unit distance avoiding sets have over-represented distance 2\approx 2 pairs, and that this clustering extends to typical unit distance avoiding sets. To do so, we build off of the linear programming approach used previously to prove upper bounds on the density of unit distance avoiding sets.

Keywords

Cite

@article{arxiv.2407.05071,
  title  = {Clustering in typical unit-distance avoiding sets},
  author = {Alex Cohen and Nitya Mani},
  journal= {arXiv preprint arXiv:2407.05071},
  year   = {2024}
}

Comments

20 pages, 7 figures

R2 v1 2026-06-28T17:31:17.467Z