Planar Graphs with Ore-degree at Most seven is strongly $13$-edge-colorable

Fuente: arXiv
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Main Authors: Nelson, Seth, Yu, Gexin
Format: Preprint
Published: 2025
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author Nelson, Seth
Yu, Gexin
author_facet Nelson, Seth
Yu, Gexin
contents A strong edge-coloring of a graph $G$ is a coloring of edges of $G$ such that every color class forms an induced matching. The strong chromatic index is the minimum number of colors needed to color the graph. The Ore-degree $θ(G)$ of a graph $G$ is the maximum sum of degrees of adjacent vertices. We show that every planar graph $G$ with $θ(G)\le 7$ has strong chromatic index at most $13$. This settles a conjecture of Chen et al in the planar case. We use a discharging method, and apply Combinatorial Nullstellensatz to show reducible configurations. We provide an algorithm to allow Combinatorial Nullstellansatz extracting coefficients from large polynomials.
format Preprint
id arxiv_https___arxiv_org_abs_2509_06808
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Planar Graphs with Ore-degree at Most seven is strongly $13$-edge-colorable
Nelson, Seth
Yu, Gexin
Combinatorics
A strong edge-coloring of a graph $G$ is a coloring of edges of $G$ such that every color class forms an induced matching. The strong chromatic index is the minimum number of colors needed to color the graph. The Ore-degree $θ(G)$ of a graph $G$ is the maximum sum of degrees of adjacent vertices. We show that every planar graph $G$ with $θ(G)\le 7$ has strong chromatic index at most $13$. This settles a conjecture of Chen et al in the planar case. We use a discharging method, and apply Combinatorial Nullstellensatz to show reducible configurations. We provide an algorithm to allow Combinatorial Nullstellansatz extracting coefficients from large polynomials.
title Planar Graphs with Ore-degree at Most seven is strongly $13$-edge-colorable
topic Combinatorics
url https://arxiv.org/abs/2509.06808