Hans Julius Zassenhaus

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Hans Julius Zassenhaus (1987)

Hans Julius Zassenhaus (born May 28, 1912 in Koblenz , † November 21, 1991 in Columbus , Ohio ) was a German mathematician , famous for his work on algebra and as a pioneer of computer algebra .

Life

Title page of the dissertation from 1934 (special edition of the journal)

Zassenhaus was a Rhinelander from Koblenz, but the family moved to Hamburg in 1916. He rejected his original wish to become a physicist and instead became a student of Erich Hecke and Emil Artin in Hamburg , where he wrote his doctoral thesis in 1934 with the title Characterization of finite linear groups as permutation groups . In it he introduced permutation groups , the " Zassenhaus groups ", which play an important role in the later classification of the finite simple groups (work by Suzuki and others). In the same year he published a new proof of the Jordan-Holder theorem in group theory (with a lemma named after him ). Schur-Zassenhaus's group theory theorem is also associated with his name. From 1934 to 1936 he was at the University of Rostock , where he wrote his group theory textbook, like van der Waerden in his algebra after lectures by Emil Artin . In 1936 he completed his habilitation as Artin's assistant in Hamburg with a thesis on Lierings about bodies with prime number characteristics (modular Lie algebras). During the Second World War he worked alongside his university work in the navy for weather forecasting (and not, as is actually obvious, in cryptography) and was involved in the resistance.

In 1943 he was offered a professorship in Bonn , which he refused - he asked that the decision be postponed “until after the war”. In 1948/49 he was in Glasgow, and then from 1949 to 1959 he was a professor at McGill University in Montreal . He then worked for five years at the University of Notre Dame and moved to Ohio State University in 1964 , where he stayed until his retirement .

He developed several algorithms in algebra and algebraic number theory (calculation of class groups, Galois groups , units, etc.). The Zassenhaus algorithm for determining the intersection and sum bases of two subspaces in linear algebra was named after him . He was a pioneer in the use of computers in the 1960s (partly in collaboration with Olga Taussky-Todd ).

He later returned several times to the theoretical physics he had initially studied , for example in a series of works with Jiří Patera and Pavel Winternitz on the subgroup structure in the physics of important Lie groups and in contributions to the colloquia Group theoretical methods in physics . He also worked on algorithms for the classification of crystallographic space groups (here, too, a Zassenhaus algorithm is named after him) and in the geometry of numbers. In the mathematical-historical field, he edited Hermann Minkowski's letters to David Hilbert and also wrote about the mathematical contrast between the two, although he saw himself more as a consequence of Minkowski. In various essays, Zassenhaus also thought about pedagogical issues.

In 1962 he gave a lecture at the International Congress of Mathematicians in Stockholm ( The Lie algebras with a non degenerate trace form , with Richard E. Block ). In 1969 he was the founding editor of the Journal of Number Theory .

He was the older brother of the doctor and author Hiltgunt Zassenhaus . Zassenhaus had been married since 1942 and had three children.

His mathematical legacy is kept in the Central Archives for Mathematicians' Legacies at the Göttingen University Library.

Fonts

literature

  • Horst Tietz : Experienced history , communications German Mathematicians Association 1999, No. 4 (Zassenhaus in World War II)
  • Wilhelm Plesken : Hans Zassenhaus (PDF; 8.8 MB) . In: Annual Report of the German Mathematicians Association , Volume 96, 1994, pp. 1-20

Web links

Commons : Hans Julius Zassenhaus  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Perhaps also because his Hamburg colleague Ernst Witt worked there, from whose National Socialist attitude he differed completely
  2. ^ Memories of Horst Tietz and von Zassenhaus' sister. To cover himself and others, he was officially a member of the party.
personal data
SURNAME Zassenhaus, Hans Julius
BRIEF DESCRIPTION German-American mathematician
DATE OF BIRTH May 28, 1912
PLACE OF BIRTH Koblenz
DATE OF DEATH November 21, 1991
Place of death Columbus (Ohio) , USA