William Thurston in 1991
William Paul Thurston
October 30, 1946
Washington, D.C., United States
|Died||August 21, 2012 (aged 65)|
Rochester, New York, United States
|Alma mater||New College of Florida|
University of California, Berkeley
|Known for||Thurston's geometrization conjecture|
Thurston's theory of surfaces
Milnor-Thurston kneading theory
|Awards||Fields Medal (1982)|
Oswald Veblen Prize in Geometry (1976)
Alan T. Waterman Award (1979)
National Academy of Sciences (1983)
Leroy P. Steele Prize (2012).
University of California, Davis
Mathematical Sciences Research Institute
University of California, Berkeley
Massachusetts Institute of Technology
Institute for Advanced Study
|Doctoral advisor||Morris Hirsch|
|Doctoral students||Richard Canary|
William Paul Thurston (October 30, 1946 – August 21, 2012) was an American mathematician. He was a pioneer in the field of low-dimensional topology. In 1982, he was awarded the Fields Medal for his contributions to the study of 3-manifolds. From 2003 until his death he was a professor of mathematics and computer science at Cornell University.
His early work, in the early 1970s, was mainly in foliation theory. His more significant results include:
In fact, Thurston resolved so many outstanding problems in foliation theory in such a short period of time that it led to an exodus from the field, where advisors counselled students against going into foliation theory, because Thurston was "cleaning out the subject" (see "On Proof and Progress in Mathematics", especially section 6).
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His later work, starting around the mid-1970s, revealed that hyperbolic geometry played a far more important role in the general theory of 3-manifolds than was previously realised. Prior to Thurston, there were only a handful of known examples of hyperbolic 3-manifolds of finite volume, such as the Seifert-Weber space. The independent and distinct approaches of Robert Riley and Troels Jørgensen in the mid-to-late 1970s showed that such examples were less atypical than previously believed; in particular their work showed that the figure-eight knot complement was hyperbolic. This was the first example of a hyperbolic knot.
Inspired by their work, Thurston took a different, more explicit means of exhibiting the hyperbolic structure of the figure-eight knot complement. He showed that the figure-eight knot complement could be decomposed as the union of two regular ideal hyperbolic tetrahedra whose hyperbolic structures matched up correctly and gave the hyperbolic structure on the figure-eight knot complement. By utilizing Haken's normal surface techniques, he classified the incompressible surfaces in the knot complement. Together with his analysis of deformations of hyperbolic structures, he concluded that all but 10 Dehn surgeries on the figure-eight knot resulted in irreducible, non-Haken non-Seifert-fibered 3-manifolds. These were the first such examples; previously it had been believed that except for certain Seifert fiber spaces, all irreducible 3-manifolds were Haken. These examples were actually hyperbolic and motivated his next theorem.
Thurston proved that in fact most Dehn fillings on a cusped hyperbolic 3-manifold resulted in hyperbolic 3-manifolds. This is his celebrated hyperbolic Dehn surgery theorem.
To complete the picture, Thurston proved a hyperbolization theorem for Haken manifolds. A particularly important corollary is that many knots and links are in fact hyperbolic. Together with his hyperbolic Dehn surgery theorem, this showed that closed hyperbolic 3-manifolds existed in great abundance.
The geometrization theorem has been called Thurston's Monster Theorem, due to the length and difficulty of the proof. Complete proofs were not written up until almost 20 years later. The proof involves a number of deep and original insights which have linked many apparently disparate fields to 3-manifolds.
Thurston was next led to formulate his geometrization conjecture. This gave a conjectural picture of 3-manifolds which indicated that all 3-manifolds admitted a certain kind of geometric decomposition involving eight geometries, now called Thurston model geometries. Hyperbolic geometry is the most prevalent geometry in this picture and also the most complicated. The conjecture was proved by Grigori Perelman in 2002-2003.
In his work on hyperbolic Dehn surgery, Thurston realized that orbifold structures naturally arose. Such structures had been studied prior to Thurston, but his work, particularly the next theorem, would bring them to prominence. In 1981, he announced the orbifold theorem, an extension of his geometrization theorem to the setting of 3-orbifolds. Two teams of mathematicians around 2000 finally finished their efforts to write down a complete proof, based mostly on Thurston's lectures given in the early 1980s in Princeton. His original proof relied partly on Richard S. Hamilton's work on the Ricci flow.
Thurston was born in Washington, D.C. to a homemaker and an aeronautical engineer. He received his bachelor's degree from New College (now New College of Florida) in 1967. For his undergraduate thesis he developed an intuitionist foundation for topology. Following this, he earned a doctorate in mathematics from the University of California, Berkeley, in 1972. His Ph.D. advisor was Morris Hirsch and his dissertation was on Foliations of Three-Manifolds which are Circle Bundles.
After completing his Ph.D., he spent a year at the Institute for Advanced Study, then another year at MIT as Assistant Professor. In 1974, he was appointed Professor of Mathematics at Princeton University. He and his first wife, Rachel Findley, had three children: Dylan, Nathaniel, and Emily. Thurston later remarried, and in 2003 he and his family moved to Ithaca, New York, where he became Professor of Mathematics at Cornell University.
His Ph.D. students include Danny Calegari, Richard Canary, David Gabai, William Goldman, Benson Farb, Richard Kenyon, Steven Kerckhoff, Yair Minsky, Igor Rivin, Oded Schramm, Richard Schwartz, William Floyd, and Jeffrey Weeks. His son Dylan Thurston is a professor of mathematics at Indiana University.
In later years Thurston widened his attention to include mathematical education and bringing mathematics to the general public. He has served as mathematics editor for Quantum Magazine, a youth science magazine, and was one of the founders of The Geometry Center. As director of Mathematical Sciences Research Institute from 1992 to 1997, he initiated a number of programs designed to increase awareness of mathematics among the public.
In 2005 Thurston won the first AMS Book Prize, for Three-dimensional Geometry and Topology. The prize "recognizes an outstanding research book that makes a seminal contribution to the research literature".
Thurston and his family had been in the process of moving back to Davis, California, where he was to rejoin the mathematics faculty at UC Davis while his wife completed her veterinary medical degree. Thurston died before he could make the move to California. He had remained with his brother George in Rochester, New York, while his family went ahead of him to California to get settled, waiting for him to gain better physical strength for making the cross-country trip to California to join them. Thurston's health declined rapidly, and the family returned to Rochester to be with him during his final days.