English

A cap covering theorem

Metric Geometry 2022-08-10 v2 Combinatorics Functional Analysis

Abstract

A cap of spherical radius α\alpha on a unit dd-sphere SS is the set of points within spherical distance α\alpha from a given point on the sphere. Let F\mathcal F be a finite set of caps lying on SS. We prove that if no hyperplane through the center of S S divides F\mathcal F into two non-empty subsets without intersecting any cap in F\mathcal F, then there is a cap of radius equal to the sum of radii of all caps in F\mathcal F covering all caps of F\mathcal F provided that the sum of radii is less π/2\pi/2. This is the spherical analog of the so-called Circle Covering Theorem by Goodman and Goodman and the strengthening of Fejes T\'oth's zone conjecture proved by Jiang and the author arXiv:1703.10550.

Keywords

Cite

@article{arxiv.2006.02192,
  title  = {A cap covering theorem},
  author = {Alexandr Polyanskii},
  journal= {arXiv preprint arXiv:2006.02192},
  year   = {2022}
}

Comments

6 pages, 2 figures. Combinatorica, accepted. Key words: Bang's plank theorem, coverings

R2 v1 2026-06-23T16:01:27.098Z