Abstract
An odd hole is an induced odd cycle of length at least five. Let \(\ell \ge 2\) be an integer, and let \({\mathcal {G}}_\ell \) denote the family of graphs which have girth \(2\ell + 1\) and have no holes of odd length at least \(2\ell +5\). In this paper, we prove that every graph \(G \in \cup _{\ell \ge 3}{\mathcal {G}}_\ell \) is 4-colourable.
Similar content being viewed by others
Data Availability
Data sharing not applicable to this paper as no datasets were generated or analysed during the current study.
References
Bondy, J., Murty, U.: Graph theory. In: GTM, vol. 244, Springer, Berlin (2008)
Chudnovsky, M., Seymour, P.: Proof of a conjecture of Plummer and Zha. J. Graph Theory 1–14 (2023)
Lan, K., Liu, F., Zhou, Y.: A note on a conjecture of Wu, Xu and Xu. Discret. Appl. Math. 326, 33–36 (2023)
Nelson, D., Plummer, M., Robertson, N., Zha, X.: On a conjecture concerning the Petersen graph. Electron. J. Combin. 18, 20 (2011)
Plummer, M., Zha, X.: On a conjecture concerning the Petersen graph: part II. Electron. J. Combin. 21, 1–34 (2014)
West, D.: Introduction to Graph Theory. Prentice Hall Inc., Hoboken (1996)
Wu, D., Xu, B., Xu, Y.: On coloring of graphs of girth \(2\ell +1\) without longer odd holes (in Chinese). Sci. China Math. 53, 103–120 (2023)
Wu, D., Xu, B., Xu, Y.: The chromatic number of heptagraphs. arXiv:2206.01400 (2022)
Xu, B., Yu, G., Zha, X.: A note on chromatic number and induced odd cycles. Electron. J. Combin. 24(4), 4–32 (2017)
Xu, Y.: On the structure of pentagraphs. Appl. Math. Comput. 439, 127632 (2023)
Acknowledgements
We would like to thank the anonymous referee for his/her careful reading and valuable suggestions. We also would like to thanks Yidong Zhou for inspiring discussions on this subject.
Funding
This research was supported by the NSFC grant 12271170 and Science and Technology Commission of Shanghai Municipality (STCSM) grant 22DZ2229014.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Lan, K., Liu, F. The Chromatic Number of a Graph with Two Odd Holes and an Odd Girth. Graphs and Combinatorics 39, 125 (2023). https://doi.org/10.1007/s00373-023-02723-y
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00373-023-02723-y