Rich-neighbor 5-edge-colorings of subcubic graphs whose 3-vertices induce a matching
Abstract
Let φ be a proper edge-coloring of a graph G. An edge is called rich if all edges adjacent to it receive pairwise distinct colors. The coloring φ is a rich-neighbor edge-coloring if every non-isolated edge is adjacent to a rich edge. Petruševski and Škrekovski introduced this notion as a relaxation of strong edge-coloring and conjectured that every connected subcubic graph other than K4 admits a rich-neighbor $5$-edge-coloring. We establish the conjectured bound for every subcubic graph G satisfying Δ(G[V3])≤ 1, where V3 is the set of vertices of degree $3$ in G. Equivalently, the $3$-vertices of G induce a matching together with isolated vertices. This extends the result of Chen, Tan and Zhou for subcubic graphs with no adjacent $3$-vertices.
Related
BibTeX
@misc{kong2026richneighbor,
title = {{Rich-neighbor 5-edge-colorings of subcubic graphs whose 3-vertices induce a matching}},
author = {Jiangxu Kong and Zhuming Lin and Yan Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21868},
eprint = {2610.21868},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21868},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Rich-neighbor 5-edge-colorings of subcubic graphs whose 3-vertices induce a matching
AU - Jiangxu Kong
AU - Zhuming Lin
AU - Yan Wang
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21868
UR - https://arxiv.org/abs/2610.21868
AB - Let φ be a proper edge-coloring of a graph G. An edge is called rich if all edges adjacent to it receive pairwise distinct colors. The coloring φ is a rich-neighbor edge-coloring if every non-isolated edge is adjacent to a rich edge. Petruševski and Škrekovski introduced this notion as a relaxation of strong edge-coloring and conjectured that every connected subcubic graph other than K_4 admits a rich-neighbor $5$-edge-coloring. We establish the conjectured bound for every subcubic graph G satisfying Δ(G[V_3])≤ 1, where V_3 is the set of vertices of degree $3$ in G. Equivalently, the $3$-vertices of G induce a matching together with isolated vertices. This extends the result of Chen, Tan and Zhou for subcubic graphs with no adjacent $3$-vertices.
ER -