English

On the orthogonal Gr\"unbaum partition problem in dimension three

Combinatorics 2024-10-04 v3 Computational Geometry

Abstract

Gr\"unbaum's equipartition problem asked if for any measure μ\mu on Rd\mathbb{R}^d there are always dd hyperplanes which divide Rd\mathbb{R}^d into 2d2^d μ\mu-equal parts. This problem is known to have a positive answer for d3d\le 3 and a negative one for d5d\ge 5. A variant of this question is to require the hyperplanes to be mutually orthogonal. This variant is known to have a positive answer for d2d\le 2 and there is reason to expect it to have a negative answer for d3d\ge 3. In this note we exhibit measures that prove this. Additionally, we describe an algorithm that checks if a set of 8n8n in R3\mathbb{R}^3 can be split evenly by 33 mutually orthogonal planes. To our surprise, it seems the probability that a random set of 88 points chosen uniformly and independently in the unit cube does not admit such a partition is less than 0.0010.001.

Keywords

Cite

@article{arxiv.2404.01504,
  title  = {On the orthogonal Gr\"unbaum partition problem in dimension three},
  author = {Gerardo L. Maldonado and Edgardo Roldán-Pensado},
  journal= {arXiv preprint arXiv:2404.01504},
  year   = {2024}
}
R2 v1 2026-06-28T15:40:52.669Z