Helmut Wielandt

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Helmut Wielandt

Helmut Wielandt (born December 19, 1910 in Niedereggenen ; † February 14, 2001 in Schliersee ) was a German mathematician . His main area of ​​work was group theory , especially the theory of permutation groups .

Wielandt's proof of Sylow's theorems , which are fundamental to the theory of finite groups, is standard worldwide today. The concept of the subnormal subgroup also goes back to him. In addition to his group theoretical work, he also made important contributions to operator theory and the theory of matrices .

Life

Helmut Wielandt was born as the son of the pastor Rudolf Wielandt and his wife Elisabeth in the village of Niedereggenen near Lörrach . Wielandt grew up in Berlin, where he attended the Prinz-Heinrich-Gymnasium from 1917 to 1929 and then studied mathematics, physics and philosophy at the Berlin University . During his studies he met his future wife Annemarie Bothe, whom he married in 1937.

In 1934/35 Wielandt received his doctorate summa cum laude with Issai Schur and Erhard Schmidt on a topic from group theory. His subsequent efforts to find an assistant position were initially unsuccessful, despite the excellent performance. In the university business, which was increasingly shaped by National Socialism , the rather apolitical and non-partisan Wielandt was regularly passed over when filling vacant positions, despite - or perhaps because of - the advocacy of his Jewish doctoral supervisor Schur.

From 1934 to March 1938, Wielandt was able to stay afloat as a research assistant in the editing of the yearbook on the progress of mathematics at the Walter de Gruyter publishing house in Berlin. But he did not want to give up his scientific career at any price. In 1937 he was finally ready to join the NSDAP and the SA . He was a member of both organizations until he was drafted into the Wehrmacht in 1939. As an SA man, Konrad Knopp and Hellmuth Kneser were able to bring Wielandt to an assistant position at the University of Tübingen in April 1938 , despite the concerns of the teaching staff there because of the shortage of membership . It followed in February 1939 the habilitation and the appointment as a lecturer in November of the same year.

With the beginning of the Second World War , Wielandt was drafted into the army artillery in September 1939. After deployments in France and Russia he was released from November 1941 on the recommendation of the Tübingen professors Konrad Knopp and Erich Kamke for various research projects in the fields of meteorology, encryption and aerodynamics. From July 1942 until the end of the war he was a research assistant at the Kaiser Wilhelm Institute for Flow Research and the Aerodynamic Research Institute in Göttingen.

After the end of the war, Wielandt returned to Tübingen, where the French military government removed him from his position as a lecturer in August 1945 because of his membership in the SA and the NSDAP. The impeachment was reversed in October, so that Wielandt was able to resume teaching in the winter semester 1945/46. A year later, he was offered an extraordinary professorship for mathematics at the University of Mainz , and in April 1951 he returned to Tübingen, this time as full professor and successor to Konrad Knopp.

Wielandt stayed in Tübingen until his retirement in 1976, although this was interrupted by several guest stays at international universities. Two longer visiting professorships took him to the University of Wisconsin , once during the winter semester 1963 and again from the winter semester 1965 to the summer semester 1967. He was also at the National Bureau of Standards in Washington DC in 1951 and 1953 , at Caltech in 1959 , and at the 1963 University of Notre Dame , 1969 at Ohio State University , 1973 at the University of Warwick and 1974 at the Universidade de Brasilia.

Wielandt received an honorary doctorate from the University of Mainz in 1977 . In 1960 he was elected a member of the Heidelberg Academy of Sciences . In 1958 he gave a plenary lecture at the International Congress of Mathematicians in Edinburgh ( Lines of Development in the Structural Theory of Finite Groups ) and in 1962 he was Invited Speaker at the ICM in Stockholm ( Conditions for the conjugation of subgroups of finite groups ).

plant

The focus of Wielandt's work was on group theory. The "revival" of the theory of (finite) permutation groups, which has stagnated since the beginning of the 20th century, should be emphasized here, an area that Wielandt had already dealt with in his dissertation from 1934 and for which his monograph published in 1964 Finite Permutation Groups has long been the standard work.

Another important part of Wielandt's group-theoretical work was the investigation of subnormal subgroups (initially called post - invariant ) , which he introduced in his habilitation thesis A generalization of invariant subgroups in 1939, as well as his contributions to the theory of general (π) Sylow theorems.

Wielandt's preoccupation with spectral theory and matrix numerics is essentially based on his research activities during the war. The inverse iteration process named after him was developed as part of his work at the aerodynamic research institute in Göttingen. Wintner-Wielandt's theorem about Heisenberg's exchange relation of limited operators is named after him .

In addition to his actual scientific work, Wielandt was the managing editor of the Mathematische Zeitschrift from 1952 to 1972 . Harro Heuser and Bertram Huppert, among others, did their doctorates with him .

In 1939 he gave a function-theoretical characterization of the gamma function as an alternative to the axiomatic characterization of the real gamma function, the Bohr-Mollerup theorem :

Let be a holomorphic function in the right half-plane with

  • and
  • is limited in the strip

then applies .

Articles (selection)

Books

family

Helmut Wielandt had been married to Annemarie Wielandt (née Bothe) since 1937. He is the father of Erhard Wielandt and Rotraud Wielandt as well as Irmgard Wielandt.

swell

  • Volker Mehrmann, Hans Schneider: Adapt or not? The story of a mathematician in Germany from 1933–1950. In: Messages from the DMV. 2, 2002, ISSN  0942-5977 , pp. 8-14.
  • B. Huppert : Obituary for Professor Dr. Dr. hc. Helmut Wielandt. In: Annual report of the DMV. 103, 3, 2001, ISSN  0012-0456 , pp. 74-78, online (PDF; 7.24 MB) .

Web links

Biographical

photos

Other links

Individual evidence

  1. ↑ Helmut Wielandt in the Mathematics Genealogy Project (English)Template: MathGenealogyProject / Maintenance / id used
personal data
SURNAME Wielandt, Helmut
BRIEF DESCRIPTION German mathematician
DATE OF BIRTH December 19, 1910
PLACE OF BIRTH Niedereggenen
DATE OF DEATH February 14, 2001
Place of death Schliersee