Haken was born on June 21, 1928, in
Berlin, Germany. His father was Werner Haken, a physicist who had
Max Planck as a doctoral thesis advisor. In 1953, Haken earned a Ph.D. degree in mathematics from
Christian-Albrechts-Universität zu Kiel (Kiel University) and married Anna-Irmgard von Bredow, who earned a Ph.D. degree in mathematics from the same university in 1959. In 1962, they left Germany so he could accept a position as visiting professor at the
University of Illinois at Urbana-Champaign. He became a full professor in 1965, retiring in 1998. In 1976, together with colleague
Kenneth Appel at the
University of Illinois at Urbana-Champaign, Haken solved the
four-color problem: they proved that any planar graph can be
properly colored using at most four colors. Haken has introduced several ideas, including
Haken manifolds,
Kneser-Haken finiteness, and an expansion of the work of
Kneser into a theory of
normal surfaces. Much of his work has an algorithmic aspect, and he is a figure in
algorithmic topology. One of his key contributions to this field is an algorithm to detect whether a knot is unknotted. In 1978, Haken delivered an
invited address at the International Congress of Mathematicians in Helsinki. He was a recipient of the 1979
Fulkerson Prize of the
American Mathematical Society for his proof with Appel of the
four-color theorem. '' by
Philip Ording. Haken died in
Champaign, Illinois, on October 2, 2022, aged 94. ==Family==