A Note on Improved bounds for the Oriented Radius of Mixed Multigraphs

Fuente: arXiv
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Main Authors: Li, Hengzhe, Ding, Zhiwei, Liu, Jianbing, Gao, Yanhong, Zhao, Shuli
Format: Preprint
Published: 2024
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_version_ 1866917710018904064
author Li, Hengzhe
Ding, Zhiwei
Liu, Jianbing
Gao, Yanhong
Zhao, Shuli
author_facet Li, Hengzhe
Ding, Zhiwei
Liu, Jianbing
Gao, Yanhong
Zhao, Shuli
contents For a positive integer $r$, let $f(r)$ denote the smallest number such that any 2-edge connected mixed graph with radius $r$ has an oriented radius of at most $f(r)$. Recently, Babu, Benson, and Rajendraprasad significantly improved the upper bound of $f(r)$ by establishing that $f(r) \leq 1.5r^2 + r + 1$, see [Improved bounds for the oriented radius of mixed multigraphs, J. Graph Theory, 103 (2023), 674-689]. Additionally, they demonstrated that if each edge of a graph $G$ is contained within a cycle of length at most $η$, then the oriented radius of $G$ is at most $1.5rη$. The authors' results were derived through Observation 1, which served as the foundation for the development of Algorithm ORIENTOUT and Algorithm ORIENTIN. By integrating these algorithms, they obtained the improved bounds. However, an error has been identified in Observation 1, necessitating revisions to Algorithm ORIENTOUT and Algorithm ORIENTIN. In this note, we address the error and propose the necessary modifications to both algorithms, thereby ensuring the correctness of the conclusions.
format Preprint
id arxiv_https___arxiv_org_abs_2407_01612
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Note on Improved bounds for the Oriented Radius of Mixed Multigraphs
Li, Hengzhe
Ding, Zhiwei
Liu, Jianbing
Gao, Yanhong
Zhao, Shuli
Combinatorics
05C12, 05C40
For a positive integer $r$, let $f(r)$ denote the smallest number such that any 2-edge connected mixed graph with radius $r$ has an oriented radius of at most $f(r)$. Recently, Babu, Benson, and Rajendraprasad significantly improved the upper bound of $f(r)$ by establishing that $f(r) \leq 1.5r^2 + r + 1$, see [Improved bounds for the oriented radius of mixed multigraphs, J. Graph Theory, 103 (2023), 674-689]. Additionally, they demonstrated that if each edge of a graph $G$ is contained within a cycle of length at most $η$, then the oriented radius of $G$ is at most $1.5rη$. The authors' results were derived through Observation 1, which served as the foundation for the development of Algorithm ORIENTOUT and Algorithm ORIENTIN. By integrating these algorithms, they obtained the improved bounds. However, an error has been identified in Observation 1, necessitating revisions to Algorithm ORIENTOUT and Algorithm ORIENTIN. In this note, we address the error and propose the necessary modifications to both algorithms, thereby ensuring the correctness of the conclusions.
title A Note on Improved bounds for the Oriented Radius of Mixed Multigraphs
topic Combinatorics
05C12, 05C40
url https://arxiv.org/abs/2407.01612