English

Properties of $8$-contraction-critical graphs with no $K_7$ minor

Combinatorics 2022-08-23 v2

Abstract

Motivated by the famous Hadwiger's Conjecture, we study the properties of 88-contraction-critical graphs with no K7K_7 minor; we prove that every 88-contraction-critical graph with no K7K_7 minor has at most one vertex of degree 88, where a graph GG is 88-contraction-critical if GG is not 77-colorable but every proper minor of GG is 77-colorable. This is one step in our effort to prove that every graph with no K7K_7 minor is 77-colorable, which remains open.

Keywords

Cite

@article{arxiv.2208.07335,
  title  = {Properties of $8$-contraction-critical graphs with no $K_7$ minor},
  author = {Martin Rolek and Zi-Xia Song and Robin Thomas},
  journal= {arXiv preprint arXiv:2208.07335},
  year   = {2022}
}