Quantitative selection theorems

Fuente: arXiv
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Main Author: Dillon, Travis
Format: Preprint
Published: 2025
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author Dillon, Travis
author_facet Dillon, Travis
contents The point selection theorem says that the convex hull of any finite point set contains a point that lies in a positive proportion of the simplices determined by that set. This paper proves several new volumetric versions of this theorem which replace the points by sets of large volume, including the first volumetric selection theorem for $(d+1)$-tuples. As consequences, we significantly decrease the upper bound for the number of sets necessary in a volumetric weak $ε$-net, from $O_d(ε^{-d^2(d+3)^2/4})$ to $O_d(ε^{-(d+1)})$, and substantially reduce the the piercing number for volumetric $(p,q)$-theorems. We also prove a volumetric version of the homogeneous point selection theorem. To do so, we introduce a volumetric same-type lemma and a new volumetric colorful Tverberg theorem. We prove all of our results for diameter as well as volume.
format Preprint
id arxiv_https___arxiv_org_abs_2508_16965
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantitative selection theorems
Dillon, Travis
Metric Geometry
Combinatorics
The point selection theorem says that the convex hull of any finite point set contains a point that lies in a positive proportion of the simplices determined by that set. This paper proves several new volumetric versions of this theorem which replace the points by sets of large volume, including the first volumetric selection theorem for $(d+1)$-tuples. As consequences, we significantly decrease the upper bound for the number of sets necessary in a volumetric weak $ε$-net, from $O_d(ε^{-d^2(d+3)^2/4})$ to $O_d(ε^{-(d+1)})$, and substantially reduce the the piercing number for volumetric $(p,q)$-theorems. We also prove a volumetric version of the homogeneous point selection theorem. To do so, we introduce a volumetric same-type lemma and a new volumetric colorful Tverberg theorem. We prove all of our results for diameter as well as volume.
title Quantitative selection theorems
topic Metric Geometry
Combinatorics
url https://arxiv.org/abs/2508.16965