PreprintCC BY 4.0arXiv
A proof of the resistance diameter conjecture for line graphs
Abstract
We prove the conjecture of Xu, Li, Hua, and Pan that the resistance diameter does not increase under the line-graph operation. For every finite connected simple graph G with at least one edge, we establish Dr(L(G))≤ Dr(G), with equality if and only if G is a cycle or K4. The proof combines an exact electrical representation of L(G) by stars with a sharp budget inequality for the branch core. This inequality controls the combined error terms arising from the comparison of degree-two paths and is central to both the diameter bound and the equality analysis.
Related
- A proof of the Murty--Simon conjecture on diameter-$2$-critical graphs
- Proof of the Göbel-Veldman conjecture on diametrical graphs
- A Proof of the Tratnik-Ye Medianity Conjecture of Resonance Graphs on Surfaces
- A Complete Proof of the Strong Conjecture about F-Irregular Graphs
- A proof of the maximum Laplacian energy conjecture for connected graphs via a sharp eigenvalue-sum bound
BibTeX
@misc{pan2026proof,
title = {{A proof of the resistance diameter conjecture for line graphs}},
author = {Xiang-Feng Pan and Xiang-Yang Liu and Zhen-Mu Hong},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.15133},
eprint = {2609.15133},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.15133},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A proof of the resistance diameter conjecture for line graphs
AU - Xiang-Feng Pan
AU - Xiang-Yang Liu
AU - Zhen-Mu Hong
PY - 2026
DA - 2026/09/14
PB - arXiv
DO - 10.48550/arxiv.2609.15133
UR - https://arxiv.org/abs/2609.15133
AB - We prove the conjecture of Xu, Li, Hua, and Pan that the resistance diameter does not increase under the line-graph operation. For every finite connected simple graph G with at least one edge, we establish D_r(L(G))≤ D_r(G), with equality if and only if G is a cycle or K_4. The proof combines an exact electrical representation of L(G) by stars with a sharp budget inequality for the branch core. This inequality controls the combined error terms arising from the comparison of degree-two paths and is central to both the diameter bound and the equality analysis.
ER -