an:01076870
Zbl 0883.05056
Robertson, Neil; Sanders, Daniel; Seymour, Paul; Thomas, Robin
The four-colour theorem
EN
J. Comb. Theory, Ser. B 70, No. 1, 2-44 (1997).
00040415
1997
j
05C15
four colour theorem; planar graph; vertex colouring
The four-colour theorem, that every loopless planar graph has a vertex colouring with at most four colours, was proved by Appel and Haken in 1976, using a computer. Here another proof is given, still using a computer, but simpler than the original.
C.Jagger (Cambridge)