Hans Wittich

Wittich (middle) 1961 in Oberwolfach

Hans Wittich (born May 4, 1911 in Lendorf near Borken in Hesse , † August 1, 1984 in Karlsruhe ) was a German mathematician .

Wittich studied at the universities in Marburg an der Lahn and Göttingen . In Göttingen he received his doctorate in 1936 with a dissertation on the subject of a criterion for determining the type of Riemann surfaces with Egon Ullrich . In 1939 he completed his habilitation. During the Second World War , from 1940–1942 he was a research assistant at the Aerodynamic Research Institute in Göttingen and dealt with conforming images in aerodynamics . Until 1947 he was a private lecturer at the Göttingen University. Then he became an associate professor at the Technical University in Karlsruhe. In 1952 he became professor of mathematics there. In 1961/62 he was visiting professor at the University of Zurich .

His main area of ​​work was function theory and, in particular, the Nevanlinnasche value distribution theory . One focus was the reversal problem ( solved by David Drasin in 1977 ) in the Nevanlinna theory. The so-called type problem of Riemann surfaces is important for this. He introduced an essential aid here with the Teichmüller-Wittich distortion theorem, named after him and Teichmüller . (According to a further generalization by Pawel Petrowitsch Belinski , one speaks today of the Teichmüller-Wittich-Belinskii distortion theorem .) Another important focus of Wittich's work was the theory of differential equations in the complex. In particular, he used the Nevanlinnasche value distribution theory and established it as an essential tool in the field of complex differential equations. Many of his results up to 1955 can be found in his treatise Newer Investigations into Unambiguous Analytical Functions , which appeared that year .

literature

• Günter Frank, Erwin Mues: Hans Wittich (1911-1984) . Results in Mathematics, Volume 10, 1986, pp. 1-7.
• Walther Killy, Rudolf Vierhaus (ed.): German Biographical Encyclopedia. Volume 10 KG Saur, Munich 1999, p. 548

Web links

• Literature by and about Hans Wittich in the catalog of the German National Library