Barycentric cuts through a convex body
Abstract
Let be a convex body in (i.e., a compact convex set with nonempty interior). Given a point in the interior of , a hyperplane passing through is called barycentric if is the barycenter of . In 1961, Gr\"{u}nbaum raised the question whether, for every , there exists an interior point through which there are at least distinct barycentric hyperplanes. Two years later, this was seemingly resolved affirmatively by showing that this is the case if is the point of maximal depth in . However, while working on a related question, we noticed that one of the auxiliary claims in the proof is incorrect. Here, we provide a counterexample; this re-opens Gr\"unbaum's question. It follows from known results that for , there are always at least three distinct barycentric cuts through the point of maximal depth. Using tools related to Morse theory we are able to improve this bound: four distinct barycentric cuts through are guaranteed if .
Cite
@article{arxiv.2003.13536,
title = {Barycentric cuts through a convex body},
author = {Zuzana Patáková and Martin Tancer and Uli Wagner},
journal= {arXiv preprint arXiv:2003.13536},
year = {2020}
}
Comments
19 pages, 7 figures