English

The overfull conjecture on graphs of odd order and large minimum degree

Combinatorics 2022-06-28 v2

Abstract

Let GG be a simple graph with maximum degree Δ(G)\Delta(G). A subgraph HH of GG is overfull if E(H)>Δ(G)12V(H)|E(H)|>\Delta(G)\lfloor \frac{1}{2}|V(H)| \rfloor. Chetwynd and Hilton in 1986 conjectured that a graph GG with Δ(G)>13V(G)\Delta(G)>\frac{1}{3}|V(G)| has chromatic index Δ(G)\Delta(G) if and only if GG contains no overfull subgraph. Let 0<ε<10<\varepsilon <1 and GG be a large graph on nn vertices with minimum degree at least 12(1+ε)n\frac{1}{2}(1+\varepsilon)n. It was shown that the conjecture holds for GG if nn is even. In this paper, the same result is proved if nn is odd. As far as we know, this is the first result on the conjecture for graphs of odd order and with a minimum degree constraint.

Cite

@article{arxiv.2205.08564,
  title  = {The overfull conjecture on graphs of odd order and large minimum degree},
  author = {Songling Shan},
  journal= {arXiv preprint arXiv:2205.08564},
  year   = {2022}
}

Comments

arXiv admin note: substantial text overlap with arXiv:2105.05286, arXiv:2104.06253; text overlap with arXiv:1010.5192 by other authors