Nikolaus Hofreiter
Nikolaus Hofreiter ( born May 8, 1904 in Linz -Urfahr; † 23 January 1990) was an Austrian mathematician who primarily worked on number theory.
Life
Nikolaus Hofreiter, whose mother brought a leather factory in the family, attended the grammar school in Linz and studied from 1923 in Vienna with Hans Hahn, Wilhelm Wirtinger, Emil Müller ( Vienna University of Technology on descriptive geometry ) and Philipp Furtwängler, in which he presented in 1927 received his doctorate with a thesis from the reduction theory of quadratic forms ( a new reduction theory for definite quadratic forms). In 1928 he passed the teaching examination and also completed the probationary year as a teacher in Vienna, but then went back to the university ( first advance as a scientific assistant at the Vienna University of Technology ), where he became in 1929 assistant to Furtwängler and in 1933 his habilitation. He was regarded even then as an outstanding teacher and held not only in Vienna, but also in Graz lectures.
In his dissertation and habilitation thesis, he discusses the reduction theory of quadratic forms, which was treated by Gauss in particular by Charles Hermite and Hermann Minkowski. Hofreiter treated the case of four variables of a problem of Minkowski ( the latter had solved for two and Robert Remak for three variables) via the product of inhomogeneous linear forms and achieved significant progress, the complete solution was not until 15 years later (and the general case is to today unresolved ). In number theory he also proved in 1934 the existence of infinitely many real quadratic number fields without Euclidean algorithm. He also dealt with the geometry of numbers and diophantine approximations.
In 1939 he became an associate professor and married the mathematician Dostalik Margaret ( 1912-2013 ), who was also a student of Furtwängler, under the tutelage of this teaching certificate and graduated with a major work on algebraic equations. She was working as a meteorologist in Berlin. During the Second World War, he had to engage in Vienna in 1939 and was later transferred to the Aeronautical Research Institute in Braunschweig, Hermann Goering, where there were already his colleague Wolfgang Gröbner from Vienna, Bernhard Baule from Graz, Ernst Josef Peschl and leaves. He also managed to bring his wife Margarete there. Was stimulated by the practical work in the aerospace research where the idea originated, surrendered along with Gröbner an integral panel. The first part of indefinite integrals appeared in 1944 as Notdruck in Braunschweig and 1949 by Springer; 1950 was followed by the more difficult second part of definite integrals. The panels were widely spread to the 5th edition of 1973/75. His wife Margaret has both parts of the integral panel checked by control calculations, while foliage has also participated in the preparation and review of the formulas and wrote the final clean copy.
Hofreiter and Gröbner could hold at the Aeronautical Research Institute in addition to their work also lectures and seminars, and later at the TU Braunschweig. After the war he returned to Vienna in 1946 and was immediately able to take back his lecturing again and continue his number-theoretic work, but increasingly he turned to the linear optimization and numerical mathematics. In 1954 he became a full professor, 1963/64, the dean of the faculty and 1965/66 he was rector of the University of Vienna. In 1974 he became Professor Emeritus, but continued to hold lectures, mainly on descriptive geometry and introductions to programming.
In 1970 he became a corresponding member of the Austrian Academy of Sciences. He received the Cross of Honor for Science and Art, First Class, the Medal of Honor of the federal capital Vienna in gold, the Great Silver Medal for Services to the Republic of Austria, the Commander's Cross of St Gregory and the Honorary Ring of the Austrian Mathematical Society. He was also honorary senator of the University of Linz.
His doctoral include Edmund Hlawka, Peter Gruber and Schmetterer.