Wolfgang Haken

Wolfgang Haken (June 21, 1928 – October 2, 2022) was a German American mathematician who specialized in topology, in particular 3-manifolds.

Biography
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.

Haken died in Champaign, Illinois, on October 2, 2022, aged 94.

Family
Haken's eldest son, Armin, proved that there exist propositional tautologies that require resolution proofs of exponential size. Haken's eldest daughter, Dorothea Blostein, is a professor of computer science, known for her discovery of the master theorem for divide-and-conquer recurrences. Haken’s second son, Lippold, is the inventor of the Continuum Fingerboard. Haken’s youngest son, Rudolf, is a professor of music, who established the world's first Electric Strings university degree program at the University of Illinois at Urbana-Champaign. Wolfgang is the cousin of Hermann Haken, a physicist known for laser theory and synergetics.