English

On the complexity of colouring antiprismatic graphs

Discrete Mathematics 2023-10-23 v1 Combinatorics

Abstract

A graph G is prismatic if for every triangle T of G, every vertex of G not in T has a unique neighbour in T. The complement of a prismatic graph is called \emph{antiprismatic}. The complexity of colouring antiprismatic graphs is still unknown. Equivalently, the complexity of the clique cover problem in prismatic graphs is not known. Chudnovsky and Seymour gave a full structural description of prismatic graphs. They showed that the class can be divided into two subclasses: the orientable prismatic graphs, and the non-orientable prismatic graphs. We give a polynomial time algorithm that solves the clique cover problem in every non-orientable prismatic graph. It relies on the the structural description and on later work of Javadi and Hajebi. We give a polynomial time algorithm which solves the vertex-disjoint triangles problem for every prismatic graph. It does not rely on the structural description.

Keywords

Cite

@article{arxiv.1910.11001,
  title  = {On the complexity of colouring antiprismatic graphs},
  author = {Myriam Preissmann and Cléophée Robin and Nicolas Trotignon},
  journal= {arXiv preprint arXiv:1910.11001},
  year   = {2023}
}