Hans Lewy | |
|---|---|
 Hans Lewy in 1975 (photo by George Bergman) | |
| Born | (1904-10-20)October 20, 1904 |
| Died | August 23, 1988(1988-08-23) (aged 83) |
| Nationality | American |
| Alma mater | University of Göttingen |
| Known for | Courant–Friedrichs–Lewy condition,Lewy's example |
| Awards | Wolf Prize (1986)[1] |
| Scientific career | |
| Fields | Mathematical analysis,partial differential equations,Function of several complex variables |
| Doctoral advisor | Richard Courant[2] |
| Doctoral students | David Kinderlehrer |
Hans Lewy (20 October 1904 – 23 August 1988) was an Americanmathematician, known for his work onpartial differential equations and on thetheory of functions of several complex variables.[3]
Lewy was born to aJewish family inBreslau,Silesia, on October 20, 1904. He began his studies at theUniversity of Göttingen in 1922, after being advised to avoid the more localUniversity of Breslau because it was too old-fashioned,[4][5] supporting himself during theWeimar hyperinflation by a side job doing railroad track maintenance.[5] At Göttingen, he studied both mathematics and physics; his teachers there includedMax Born,Richard Courant,James Franck,David Hilbert,Edmund Landau,Emmy Noether, andAlexander Ostrowski. He earned his doctorate in 1926, at which time he and his friendKurt Otto Friedrichs both became assistants to Courant andprivatdozents at Göttingen. The famousCourant-Friedrichs-Lewy condition originated from that time in 1928.[4][5]
At the recommendation of Courant, Lewy was granted aRockefeller Fellowship, which he used in 1929 to travel to Rome and studyalgebraic geometry withTullio Levi-Civita andFederigo Enriques, and then in 1930 to travel to Paris, where he attended the seminar ofJacques Hadamard. AfterHitler's election as chancellor in 1933, Lewy was advised byHerbert Busemann to leave Germany again. He was offered a position in Madrid, but declined it, fearing for the future there underFrancisco Franco. He revisited Italy and France, but then at the invitation of theEmergency Committee in Aid of Displaced Foreign Scholars and with the assistance of Hadamard found a two-year position in America atBrown University. At the end of that term, in 1935, he moved to theUniversity of California, Berkeley.[4][5]
DuringWorld War II, Lewy obtained a pilot's license, but then worked at theAberdeen Proving Ground. He married Helen Crosby in 1947.[5]
In 1950, Lewy was fired from Berkeley for refusing to sign a loyalty oath.[5][6][7] He taught atHarvard University andStanford University in 1952 and 1953[5] before being reinstated by theCalifornia Supreme Court caseTolman v. Underhill.[6][7]
He retired from Berkeley in 1972, and in 1973 became one of two Ordway Professors of Mathematics at theUniversity of Minnesota. He died on August 23, 1988, in Berkeley.[5][6][8]
Lewy is known for his contributions to partial differential equations. In 1957, his famous example of a second-order linear partial differential equation was so stunning and unexpected that the whole field steered in a new direction, as well as shaping modern analysis in a significant way. Based on this example,Louis Nirenberg,Lars Hörmander and others have outlined some important changes to the theory and structure of the field. This was adopted by many analysts and mathematicians as a major development.
He also worked on several complex variables in relation to nonlinear hyperbolic equations and elliptic equations, well-posedness for initial value problems of wave fronts (now commonly calledSobolev spaces) in the early 1930s, solutions of the classical problems ofHermann Weyl andHermann Minkowski for analytical data (the original problem was solved by Louis Nirenberg in 1949 as part of his PhD thesis), the extendibility ofminimal surfaces on and analytical nature of its boundaries which is fully free or in part, free boundary problems of water wave fronts in hydrodynamics, and the proof of quadratic reciprocity theorem in number theory from 'hydrodynamical' perspective.
Lewy was elected to theNational Academy of Sciences in 1964, and was also a member of theAmerican Academy of Arts and Sciences.[6] He became a foreign member of theAccademia dei Lincei in 1972.[5]He was awarded aLeroy P. Steele Prize in 1979,[5] and aWolf Prize in Mathematics in 1986 for his work on partial differential equations.[1] In 1986, theUniversity of Bonn gave him an honorary doctorate.[8]
{{cite book}}: CS1 maint: postscript (link)[9]A selection of his work, edited byDavid Kinderlehrer and including his most important works, was published as the two volume work (Kinderlehrer 2002a) and (Kinderlehrer 2002b)
The following works are included in his "Selecta" in their original language or translated form.
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