The four color theorem has been proved
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Article
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1977
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John Wiley and Sons
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English
β 26 KB
On the 21st of June 1976, which was the 48th birthday of Wolfgang Haken, he and Kenneth Appel (with the aid of John Koch) completed their proof of the Four Color Theorem. In recognition of their momentous achievement, the Journal ofGruph Theory presents two articles (by Haken and by Frank Bernhart)