English

Balanced configurations of points in the plane

Metric Geometry 2022-08-05 v1 Combinatorics

Abstract

A balanced configuration of points on the sphere S2S^2 is a (finite) set of points which are in equilibrium if they act on each other according any force law dependent only on the distance between two points. The configuration is additionally group-balanced if for each point in a configuration C\mathcal{C}, there is a symmetry of C\mathcal{C} fixing only that point and its antipode. Leech showed that these definitions are equivalent on the sphere S2S^2 by classifying all possible balanced configurations. On the other hand, Cohn, Elkies, Kumar, and Sch\"urmann showed that for n7,n\geq 7, there are examples of balanced configurations in Sn1S^{n-1} which are not group balanced. They also suggested extending the notion of balanced configurations to Euclidean space, and conjectured that at least in the case of the plane, all discrete balanced configurations in Rn\mathbb{R}^n are group-balanced. We verify a reformulation of this conjecture by providing a complete classification of the balanced configurations in R2\mathbb{R}^2 satisfying a certain minimal distance property.

Keywords

Cite

@article{arxiv.2208.02426,
  title  = {Balanced configurations of points in the plane},
  author = {Laura Pierson and Julian Wellman},
  journal= {arXiv preprint arXiv:2208.02426},
  year   = {2022}
}

Comments

22 pages, 23 figures