The Four-Colour Theorem

@article{Robertson1997TheFT,
  title={The Four-Colour Theorem},
  author={Neil Robertson and Daniel P. Sanders and Paul D. Seymour and Robin Thomas},
  journal={J. Comb. Theory, Ser. B},
  year={1997},
  volume={70},
  pages={2-44}
}
The four-colour theorem, that every loopless planar graph admits a vertex-colouring with at most four different colours, was proved in 1976 by Appel and Haken, using a computer. Here we give another proof, still using a computer, but simpler than Appel and Haken's in several respects. 

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