Wilhelm Blaschke

Wilhelm Johann Eugen Blaschke (born September 13, 1885 in Graz , † March 17, 1962 in Hamburg ) was an Austrian mathematician and author. His work has decisively influenced the development of modern differential geometry .

Life

Wilhelm Blaschke (1930)

His father Josef Blaschke (* 1852 † 1917) taught descriptive geometry at the secondary school in Graz and influenced his son early on in terms of the purely geometric evidence of Jakob Steiner . His mother was Maria Blaschke (* 1864 † 1945), née Edle von Mor zu Morberg and Sunnegg.

He studied civil engineering at the Technical University of Graz, where his turn to mathematics was reinforced by Oskar Peithner von Lichtenfels and he switched to studying mathematics at the University of Vienna and did his doctorate with Wilhelm Wirtinger in 1908 (on a special kind of curves, fourth grade). He then went to Pisa to Luigi Bianchi and to Göttingen to Felix Klein , David Hilbert and Carl Runge . In 1910 he completed his habilitation with Eduard Study in Bonn . Before he became a professor in Prague in 1913 , he worked with the Lie student Friedrich Engel in Greifswald . In 1915 he went to Leipzig , where he followed Jakob Steiner's footsteps in his inaugural lecture "Circle and Ball" , in 1917 to Königsberg and from there via Tübingen in 1919 to Hamburg , which he became a center of mathematics with the appointment of Erich Hecke and Emil Artin, among others made. He stayed there until his retirement in 1953, but continued to travel extensively afterwards. In 1927/28 he was rector of the University of Hamburg (inaugural address: Leonardo and the natural sciences).

In the Nazi state, Blaschke initially opposed its efforts to isolate itself in the scientific field, then became a member of the NSDAP . On November 11, 1933, he was one of the callers for the German professors' commitment to Adolf Hitler and the National Socialist state .

Blaschke was highly controversial in the post-war years. He was denazified in 1946 and got his chair back in Hamburg, which he held until his retirement in 1953. But even then he had a lot of international contacts. His students included the internationally leading geometer Shiing-Shen Chern after the Second World War , who received his doctorate with him in 1936, Gerhard Thomsen and Luis Santaló . Another employee was Gerrit Bol .

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Blaschke worked in numerous areas of differential geometry (especially affine differential geometry) and geometry, e.g. B. on minimal properties ("isoperimetric properties") of geometric figures, convex bodies , integral geometry (a term he coined) and the geometry of the "tissue", group-theoretical properties of geometry, geometry of circles and spheres (after Edmond Laguerre , August Ferdinand Möbius , Sophus Lie ). In function theory , the Blaschke product is named after him, as well as Blaschke's convergence theorem and Blaschke's selection theorem .

He is the author of many excellent textbooks, especially his "Lectures on Differential Geometry" from 1921/9. He has also re-edited and supplemented Felix Klein's lectures on higher geometry. Blaschke was co-editor of the basic teaching of mathematical sciences .

A conjecture by Blaschke about the characterization of the n-dimensional sphere as a reunion manifold was proven by Jerry Kazdan , Marcel Berger , Alan Weinstein and Chung Tao Yang .

Honors and memberships

On April 4, 1957, Blaschke was accepted as an honorary member of the German Academy of Sciences in Berlin . He was also a member of the Leopoldina since 1943 . He was a member of the Austrian Academy of Sciences , the Academy of Sciences and Literature in Mainz and a corresponding member of the Bavarian and Saxon Academy of Sciences and honorary doctorate from the Universities of Sofia, Padua, Karlsruhe and Greifswald.

Personal and family

Blaschke married Auguste Meta Anna Röttger (* 1893 † 1992) from Hamburg on April 10, 1923, with whom she had a daughter and a son. He died on March 17, 1962 of a heart attack as a result of appendicitis that had gone unnoticed for a long time. His grave is in the Ohlsdorf cemetery , not far from the main entrance.

Others

The Wilhelm Blaschke Memorial Foundation in Hamburg (founded by Emanuel Sperner ) awards him a medal for achievements in geometry in his honor. Prize winners included Katsumi Nomizu and Kurt Leichtweiß . His scientific legacy is in the Institute for the History of Science and Technology at the University of Hamburg.

Works

Collected works , Thales, Essen 1985
Circle and sphere , Leipzig, Veit 1916, 3rd edition, Berlin, de Gruyter 1956
Lectures on differential geometry , 3 vols., Springer, Grundlehren der Mathematischen Wissenschaften 1921-1929 (vol. 1 elementary differential geometry, vol. 2 affine differential geometry, vol. 3 differential geometry of circles and spheres, 1929)
Non-Euclidean Geometry and Mechanics I, II, III . Leipzig: BGTeubner (1942)
To the geometry of motion on the sphere . In: Meeting reports of the Heidelberg Academy of Sciences (1948)
Kinematics and Quaternions . Berlin: VEB Deutscher Verlag der Wissenschaften (1960)
with Kurt Leichtweiß : Elementary differential geometry . Berlin: Springer (5th edition 1973)
Talking and traveling of a geometer . Berlin: VEB Deutscher Verlag der Wissenschaften (1961; 2nd, extended edition)
Mathematics and Life , Wiesbaden, Steiner 1951
Projective geometry , 3rd edition, Birkhäuser 1954
Analytical Geometry , 2nd edition, Birkhäuser 1954
Introduction to differential geometry , basic teachings of the mathematical sciences, Springer 1950, 2nd edition with Hans Reichardt 1960
Circle and sphere (Leipzig inaugural lecture) in: Herbert Beckert, Walter Purkert Leipzig mathematical inaugural lectures. Selection from the years 1869-1922 , BG Teubner, Leipzig 1987 (with biography), originally DMV Annual Report, Volume 24, 1915, pp. 195–209
Lectures on integral geometry , VEB, Berlin 1955
Kinematics level , Oldenbourg, Munich 1956
with Gerrit Bol geometry of the fabric. Topological Questions in Differential Geometry , Basic Teachings of Mathematical Sciences , Springer 1938
Introduction to the geometry of honeycombs , Birkhäuser 1955
Greek and descriptive geometry , Oldenbourg 1953

literature

Hans Reichardt : Wilhelm Blaschke. In: Annual report DMV. Volume 69, 1967, pp. 1-8.
Karl Strubecker : Wilhelm Baschke's mathematical work. In: Annual report DMV. Volume 88, Issue 3, 1986, pp. 146-157.
SS Chern: The mathematical works of Wilhelm Blaschke. In: Abh. Math. Seminar Universität Hamburg. 1973.
Emanuel Sperner : In memory of Wilhelm Blaschke. In: Abh. Math. Seminar Hamburg. Volume 26, 1963/1964, p. 111.
Christoph Scriba : Blaschke, Wilhelm Johann Eugen . In: Charles Coulston Gillispie (Ed.): Dictionary of Scientific Biography . tape 2 : Hans Berger - Christoph Buys Ballot . Charles Scribner's Sons, New York 1970, p. 191-192 .
Alexander Odefey: Directory of the scientific legacy of Wilhelm Blaschke (1885–1962). In: Communications from the Mathematical Society in Hamburg. Volume 27, 2008, pp. 141-146.
Joachim Focke: Wilhelm Blaschke and his investigations into orbiforms. In: Herbert Beckert , Horst Schumann (Hrsg.): 100 Years of Mathematical Seminar at the Karl Marx University of Leipzig. German Science Publishers, Berlin 1981.

Fonts accessible online

Web links

Literature by and about Wilhelm Blaschke in the catalog of the German National Library
Newspaper article about Wilhelm Blaschke in the press kit of the 20th century of the ZBW - Leibniz Information Center for Economics .
John J. O'Connor, Edmund F. Robertson : Wilhelm Blaschke. In: MacTutor History of Mathematics archive .
Wilhelm Blaschke in the professorial catalog of the University of Leipzig

Individual evidence

^ Wilhelm Blaschke in the Mathematics Genealogy Project (English) .
↑ ^a ^b Ernst Klee : The dictionary of persons on the Third Reich. Who was what before and after 1945 . Fischer Taschenbuch Verlag, Second updated edition, Frankfurt am Main 2005, p. 52.

personal data
SURNAME	Blaschke, Wilhelm
ALTERNATIVE NAMES	Blaschke, Wilhelm Johann Eugen (full name)
BRIEF DESCRIPTION	Austrian mathematician and author
DATE OF BIRTH	September 13, 1885
PLACE OF BIRTH	Graz
DATE OF DEATH	March 17, 1962
Place of death	Hamburg

[1] Wilhelm Blaschke in the Mathematics Genealogy Project (English) .

[Klee52-2] Ernst Klee : The dictionary of persons on the Third Reich. Who was what before and after 1945 . Fischer Taschenbuch Verlag, Second updated edition, Frankfurt am Main 2005, p. 52.