English

Recolouring weakly chordal graphs and the complement of triangle-free graphs

Combinatorics 2021-07-06 v2 Discrete Mathematics

Abstract

For a graph GG, the kk-recolouring graph Rk(G)\mathcal{R}_k(G) is the graph whose vertices are the kk-colourings of GG and two colourings are joined by an edge if they differ in colour on exactly one vertex. We prove that for all n1n \ge 1, there exists a kk-colourable weakly chordal graph GG where Rk+n(G)\mathcal{R}_{k+n}(G) is disconnected, answering an open question of Feghali and Fiala. We also show that for every kk-colourable 3K13K_1-free graph GG, Rk+1(G)\mathcal{R}_{k+1}(G) is connected with diameter at most 4V(G)4|V(G)|.

Keywords

Cite

@article{arxiv.2106.11087,
  title  = {Recolouring weakly chordal graphs and the complement of triangle-free graphs},
  author = {Owen Merkel},
  journal= {arXiv preprint arXiv:2106.11087},
  year   = {2021}
}

Comments

6 pages, 2 figures