English

The Kelmans-Seymour conjecture IV: a proof

Combinatorics 2016-12-22 v1

Abstract

A well known theorem of Kuratowski in 1932 states that a graph is planar if, and only if, it does not contain a subdivision of K5K_5 or K3,3K_{3,3}. Wagner proved in 1937 that if a graph other than K5K_5 does not contain any subdivision of K3,3K_{3,3} then it is planar or it admits a cut of size at most 2. Kelmans and, independently, Seymour conjectured in the 1970s that if a graph does not contain any subdivision of K5K_5 then it is planar or it admits a cut of size at most 4. In this paper, we give a proof of the Kelmans-Seymour conjecture. We also discuss several related results and problems.

Keywords

Cite

@article{arxiv.1612.07189,
  title  = {The Kelmans-Seymour conjecture IV: a proof},
  author = {Dawei He and Yan Wang and Xingxing Yu},
  journal= {arXiv preprint arXiv:1612.07189},
  year   = {2016}
}
R2 v1 2026-06-22T17:31:03.219Z