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Main Author: Higgins, Cecelia
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2405.00991
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author Higgins, Cecelia
author_facet Higgins, Cecelia
contents We prove a descriptive version of Brooks's theorem for directed graphs. In particular, we show that, if $D$ is a Borel directed graph on a standard Borel space $X$ such that the maximum degree of each vertex is at most $d \geq 3$, then unless $D$ contains the complete symmetric directed graph on $d + 1$ vertices, $D$ admits a $μ$-measurable $d$-dicoloring with respect to any Borel probability measure $μ$ on $X$, and $D$ admits a $τ$-Baire-measurable $d$-dicoloring with respect to any Polish topology $τ$ compatible with the Borel structure on $X$. We also prove a definable version of Gallai's theorem on list dicolorings for directed graphs by showing that any Borel directed graph of bounded degree whose connected components are not Gallai trees is Borel degree-list-dicolorable.
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id arxiv_https___arxiv_org_abs_2405_00991
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Measurable Brooks's Theorem for Directed Graphs
Higgins, Cecelia
Logic
Combinatorics
We prove a descriptive version of Brooks's theorem for directed graphs. In particular, we show that, if $D$ is a Borel directed graph on a standard Borel space $X$ such that the maximum degree of each vertex is at most $d \geq 3$, then unless $D$ contains the complete symmetric directed graph on $d + 1$ vertices, $D$ admits a $μ$-measurable $d$-dicoloring with respect to any Borel probability measure $μ$ on $X$, and $D$ admits a $τ$-Baire-measurable $d$-dicoloring with respect to any Polish topology $τ$ compatible with the Borel structure on $X$. We also prove a definable version of Gallai's theorem on list dicolorings for directed graphs by showing that any Borel directed graph of bounded degree whose connected components are not Gallai trees is Borel degree-list-dicolorable.
title Measurable Brooks's Theorem for Directed Graphs
topic Logic
Combinatorics
url https://arxiv.org/abs/2405.00991