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A stronger upper bound on the D-chromatic index
Abstract
For a graph G, a proper edge coloring of G is called a D-coloring if every diamond subgraph of G is rainbow. Let χ'D(G) be the D-chromatic index of G, which is the smallest integer k such that G admits a D-coloring with k colors. Let Δ be the maximum degree of G. The only known Brooks-type upper bound on χ'D(G) is 9/16Δ2 + 1/2Δ, given by a greedy coloring. In this paper, using a probabilistic method, we obtain the first improvement upon this upper bound by proving that χ'D(G) ≤ (1−c)9/16Δ2 for some c > 0 and sufficiently large Δ.
Related
BibTeX
@misc{tian2026stronger,
title = {{A stronger upper bound on the D-chromatic index}},
author = {Lin Tian and Runze Wang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01875},
eprint = {2609.01875},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01875},
}
RIS
TY - UNPB
TI - A stronger upper bound on the D-chromatic index
AU - Lin Tian
AU - Runze Wang
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.01875
UR - https://arxiv.org/abs/2609.01875
AB - For a graph G, a proper edge coloring of G is called a D-coloring if every diamond subgraph of G is rainbow. Let χ'_D(G) be the D-chromatic index of G, which is the smallest integer k such that G admits a D-coloring with k colors. Let Δ be the maximum degree of G. The only known Brooks-type upper bound on χ'_D(G) is 9/16Δ^2 + 1/2Δ, given by a greedy coloring. In this paper, using a probabilistic method, we obtain the first improvement upon this upper bound by proving that χ'_D(G) ≤ (1−c)9/16Δ^2 for some c > 0 and sufficiently large Δ.
ER -