Edge-colouring eight-regular planar graphs

Maria Chudnovsky, Katherine Edwards, Paul Seymour

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


It was conjectured by the third author in about 1973 that every d-regular planar graph (possibly with parallel edges) can be d-edge-coloured, provided that for every odd set X of vertices, there are at least d edges between X and its complement. For d=3 this is the four-colour theorem, and the conjecture has been proved for all d≤7, by various authors. Here we prove it for d=8.

Original languageEnglish (US)
Pages (from-to)303-338
Number of pages36
JournalJournal of Combinatorial Theory. Series B
StatePublished - Nov 1 2015

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Discrete Mathematics and Combinatorics
  • Computational Theory and Mathematics


  • Discharging
  • Edge-colouring
  • Four-colour theorem
  • Planar graph
  • Reducible configuration


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