English

Colorful Borsuk--Ulam theorems and applications

Combinatorics 2023-09-27 v1 Metric Geometry

Abstract

We prove a colorful generalization of the Borsuk--Ulam theorem and derive colorful consequences from it, such as a colorful generalization of the ham sandwich theorem. Even in the uncolored case this specializes to a strengthening of the ham sandwich theorem, which given an additional condition, contains a result of B\'{a}r\'{a}ny, Hubard, and Jer\'{o}nimo on well-separated measures as a special case. We prove a colorful generalization of Fan's antipodal sphere covering theorem, we derive a short proof of Gale's colorful KKM theorem, and we prove a colorful generalization of Brouwer's fixed point theorem. Our results also provide an alternative between Radon-type intersection results and KKM-type covering results. Finally, we prove colorful Borsuk--Ulam theorems for higher symmetry.

Keywords

Cite

@article{arxiv.2309.14539,
  title  = {Colorful Borsuk--Ulam theorems and applications},
  author = {Florian Frick and Zoe Wellner},
  journal= {arXiv preprint arXiv:2309.14539},
  year   = {2023}
}

Comments

15 pages