A Note About Majority Colorings of Countable DAGs

Fuente: arXiv
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Auteurs principaux: Bosek, Bartłomiej, Katan, Aleksander
Format: Preprint
Publié: 2024
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author Bosek, Bartłomiej
Katan, Aleksander
author_facet Bosek, Bartłomiej
Katan, Aleksander
contents A majority coloring of an undirected graph is a vertex coloring in which for each vertex there are at least as many bi-chromatic edges containing that vertex as monochromatic ones. It is known that for every countable graph a majority 3-coloring always exists. The Unfriendly Partition Conjecture states that every countable graph admits a majority 2-coloring. Since the 3-coloring result extends to countable DAGs, a variant of the conjecture states that 2 colors are enough to majority color every countable DAG. We show that this is false by presenting a DAG for which 3 colors are necessary. Presented construction is strongly based on a StackExchange conversation regarding labellings of infinite graphs that is linked in the references.
format Preprint
id arxiv_https___arxiv_org_abs_2406_04189
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Note About Majority Colorings of Countable DAGs
Bosek, Bartłomiej
Katan, Aleksander
Discrete Mathematics
Combinatorics
05C15, 05C63, 05C20
G.2.1
A majority coloring of an undirected graph is a vertex coloring in which for each vertex there are at least as many bi-chromatic edges containing that vertex as monochromatic ones. It is known that for every countable graph a majority 3-coloring always exists. The Unfriendly Partition Conjecture states that every countable graph admits a majority 2-coloring. Since the 3-coloring result extends to countable DAGs, a variant of the conjecture states that 2 colors are enough to majority color every countable DAG. We show that this is false by presenting a DAG for which 3 colors are necessary. Presented construction is strongly based on a StackExchange conversation regarding labellings of infinite graphs that is linked in the references.
title A Note About Majority Colorings of Countable DAGs
topic Discrete Mathematics
Combinatorics
05C15, 05C63, 05C20
G.2.1
url https://arxiv.org/abs/2406.04189