Colorful Intersections and Tverberg Partitions

Fuente: arXiv
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Hauptverfasser: Dobbins, Michael Gene, Holmsen, Andreas F., Lee, Dohyeon
Format: Preprint
Veröffentlicht: 2024
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author Dobbins, Michael Gene
Holmsen, Andreas F.
Lee, Dohyeon
author_facet Dobbins, Michael Gene
Holmsen, Andreas F.
Lee, Dohyeon
contents The colorful Helly theorem and Tverberg's theorem are fundamental results in discrete geometry. We prove a theorem which interpolates between the two. In particular, we show the following for any integers $d \geq m \geq 1$ and $k$ a prime power. Suppose $F_1, F_2, \dots, F_m$ are families of convex sets in $\mathbb{R}^d$, each of size $n > (\frac{d}{m}+1)(k-1)$, such that for any choice $C_i\in F_i$ we have $\bigcap_{i=1}^mC_i\neq \emptyset$. Then, one of the families $F_i$ admits a Tverberg $k$-partition. That is, one of the $F_i$ can be partitioned into $k$ nonempty parts such that the convex hulls of the parts have nonempty intersection. As a corollary, we also obtain a result concerning $r$-dimensional transversals to families of convex sets in $\mathbb{R}^d$ that satisfy the colorful Helly hypothesis, which extends the work of Karasev and Montejano.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14909
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Colorful Intersections and Tverberg Partitions
Dobbins, Michael Gene
Holmsen, Andreas F.
Lee, Dohyeon
Combinatorics
Metric Geometry
The colorful Helly theorem and Tverberg's theorem are fundamental results in discrete geometry. We prove a theorem which interpolates between the two. In particular, we show the following for any integers $d \geq m \geq 1$ and $k$ a prime power. Suppose $F_1, F_2, \dots, F_m$ are families of convex sets in $\mathbb{R}^d$, each of size $n > (\frac{d}{m}+1)(k-1)$, such that for any choice $C_i\in F_i$ we have $\bigcap_{i=1}^mC_i\neq \emptyset$. Then, one of the families $F_i$ admits a Tverberg $k$-partition. That is, one of the $F_i$ can be partitioned into $k$ nonempty parts such that the convex hulls of the parts have nonempty intersection. As a corollary, we also obtain a result concerning $r$-dimensional transversals to families of convex sets in $\mathbb{R}^d$ that satisfy the colorful Helly hypothesis, which extends the work of Karasev and Montejano.
title Colorful Intersections and Tverberg Partitions
topic Combinatorics
Metric Geometry
url https://arxiv.org/abs/2403.14909