Colouring graphs of bounded diameter in the absence of small cycles

Martin, B.; Paulusma, D.; Smith, S.

Abstract

For k ≥ 1, a k-colouring c of G is a mapping from V (G) to {1, 2, . . . , k} such that c(u) 6= c(v) for any two adjacent vertices u and v. The k-Colouring problem is to decide if a graph G has a k-colouring. For a family of graphs H, a graph G is H-free if G does not contain any graph from H as an induced subgraph. Let Cs be the s-vertex cycle. In previous work (MFCS 2019) we examined the effect of bounding the diameter on the complexity of 3-Colouring for (C3, . . . , Cs)-free graphs and H-free graphs where H is some polyad. Here, we prove for certain small values of s that 3-Colouring is polynomial-time solvable for Cs-free graphs of diameter 2 and (C4, Cs)-free graphs of diameter 2. In fact, our results hold for the more general problem List 3-Colouring. We complement these results with some hardness result for diameter 4.

Citation

Martin, B., Paulusma, D., & Smith, S. (2022). Colouring graphs of bounded diameter in the absence of small cycles. Discrete Applied Mathematics, 314, 150-161. https://doi.org/10.1016/j.dam.2022.02.026

• Journal Article Type: Article
• Acceptance Date: Feb 22, 2022
• Online Publication Date: Mar 19, 2022
• Publication Date: Jun 15, 2022
• Deposit Date: May 18, 2022
• Publicly Available Date: Mar 20, 2024
• Journal: Discrete Applied Mathematics
• Print ISSN: 0166-218X
• Electronic ISSN: 1872-6771
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 314
• Pages: 150-161
• DOI: https://doi.org/10.1016/j.dam.2022.02.026
• Public URL: https://durham-repository.worktribe.com/output/1206956