Recognizing Graphs Close to Bipartite Graphs with an Application to Colouring Reconfiguration

Bonamy, M; Dabrowski, K.K; Feghali, C; Johnson, M; Paulusma, D

Abstract

We continue research into a well-studied family of problems that ask whether the vertices of a given graph can be partitioned into sets A and B, where A is an independent set and B induces a graph from some specified graph class G. We consider the case where G is the class of k-degenerate graphs. This problem is known to be polynomial-time solvable if k = 0 (recognition of bipartite graphs), but NP-complete if k = 1 (near-bipartite graphs) even for graphs of maximum degree 4. Yang and Yuan [DM, 2006] showed that the k = 1 case is polynomial-time solvable for graphs of maximum degree 3. This also follows from a result of Catlin and Lai [DM, 1995]. We study the general k ≥ 1 case for n-vertex graphs of maximum degree k + 2 We show how to find A and B in O(n) time for k = 1, and in O(n 2 ) time for k ≥ 2. Together, these results provide an algorithmic version of a result of Catlin [JCTB, 1979] and also provide an algorithmic version of a generalization of Brook’s Theorem, proved by Borodin, Kostochka and Toft [DM, 2000] and Matamala [JGT, 2007]. The results also enable us to solve an open problem of Feghali et al. [JGT, 2016]. For a given graph G and positive integer `, the vertex colouring reconfiguration graph of G has as its vertex set the set of `-colourings of G and contains an edge between each pair of colourings that differ on exactly on vertex. We complete the complexity classification of the problem of finding a path in the reconfiguration graph between two given `-colourings of a given graph of maximum degree k.

Citation

Bonamy, M., Dabrowski, K., Feghali, C., Johnson, M., & Paulusma, D. (2021). Recognizing Graphs Close to Bipartite Graphs with an Application to Colouring Reconfiguration. Journal of Graph Theory, 98(1), 81-109. https://doi.org/10.1002/jgt.22683

• Journal Article Type: Article
• Acceptance Date: Apr 3, 2021
• Online Publication Date: May 24, 2021
• Publication Date: 2021-09
• Deposit Date: Apr 7, 2021
• Publicly Available Date: Aug 6, 2021
• Journal: Journal of Graph Theory
• Print ISSN: 0364-9024
• Electronic ISSN: 1097-0118
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 98
• Issue: 1
• Pages: 81-109
• DOI: https://doi.org/10.1002/jgt.22683
• Public URL: https://durham-repository.worktribe.com/output/1278013
• Publisher URL: https://onlinelibrary.wiley.com/journal/10970118
• Related Public URLs: https://arxiv.org/abs/1707.09817