Illinois Journal of Mathematics

Wolfgang Haken and the four-color problem

Robin Wilson

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In 1852, Augustus De Morgan, Professor of Mathematics at University College, London, was asked: Can every map be colored with just four colors in such a way that neighboring countries are colored differently? Over a century later, in a controversial proof that made substantial use of a computer, Wolfgang Haken and Kenneth Appel of the University of Illinois answered the question in the affirmative. But how did Haken come to be involved with the problem, and what was his role in its solution?

Article information

Illinois J. Math., Volume 60, Number 1 (2016), 149-178.

First available in Project Euclid: 21 June 2017

Permanent link to this document

Mathematical Reviews number (MathSciNet)

Zentralblatt MATH identifier

Primary: 05C15: Coloring of graphs and hypergraphs


Wilson, Robin. Wolfgang Haken and the four-color problem. Illinois J. Math. 60 (2016), no. 1, 149--178.

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