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Wilhelm Blaschke  

Born  
Died  17 March 1962  (aged 76)
Nationality  Austrian 
Alma mater  University of Vienna 
Known for  Blaschke product Blaschke selection theorem Blaschke–Santaló inequality 
Scientific career  
Fields  Mathematics 
Institutions  University of Hamburg 
Doctoral advisor  Wilhelm Wirtinger 
Doctoral students  ShiingShen Chern Luis Santaló Emanuel Sperner 
Wilhelm Johann Eugen Blaschke (13 September 1885 – 17 March 1962) was an Austrian mathematician working in the fields of differential and Integral geometry. He was also a Nazi.
Education and career
Blaschke was the son of mathematician Josef Blaschke, who taught geometry at the Landes Oberrealschule in Graz. After studying for two years at the Technische Hochschule in Graz, he went to the University of Vienna, and completed a doctorate in 1908 under the supervision of Wilhelm Wirtinger.^{[1]} His dissertation was Über eine besondere Art von Kurven vierter Klasse.^{[2]}
After completing his doctorate he spent several years visiting mathematicians at the major universities in Italy and Germany. He spent two years each in positions in Prague, Leipzig, Göttingen, and Tübingen until, in 1919, he took the professorship at the University of Hamburg that he would keep for the rest of his career.^{[1]} His students at Hamburg included ShiingShen Chern, Luis Santaló, and Emanuel Sperner.^{[2]}
In 1933 Blaschke signed the Vow of allegiance of the Professors of the German Universities and HighSchools to Adolf Hitler and the National Socialistic State.^{[3]} However, he defended Kurt Reidemeister against the Nazis and, in the early 1930s, campaigned against Ludwig Bieberbach for leadership of the German Mathematical Society, arguing that the society should remain international and apolitical in opposition to Bieberbach's wish to "enforce Nazi policies on German mathematics and race". However, by 1936 he was supporting Nazi policies, called himself "a Nazi at Heart", and was described by colleagues as "Mussolinetto" for his fascist beliefs.^{[1]} He officially joined the Nazi Party in 1937.^{[3]}
After the war, Blaschke was removed from his position at the University of Hamburg for his Nazi affiliation, but after an appeal his professorship was restored in 1946.^{[1]} He remained at the university until his retirement in 1953.^{[1]}
Publications
In 1916 Blaschke published one of the first books devoted to convex sets: Circle and Sphere (Kreis und Kugel). Drawing on dozens of sources, Blaschke made a thorough review of the subject with citations within the text to attribute credit in a classical area of mathematics.
 Kreis und Kugel, Leipzig, Veit 1916; 3rd edn. Berlin, de Gruyter 1956
 Vorlesungen über Differentialgeometrie, 3 vols., Springer, Grundlehren der mathematischen Wissenschaften 19211929 (vol. 1, Elementare Differentialgeometrie;^{[4]} vol. 2, Affine Differentialgeometrie; vol. 3, Differentialgeometrie der Kreise und Kugeln, 1929)
 with G. Bol: Geometrie der Gewebe. Berlin: Springer 1938^{[5]}
 Ebene Kinematik. Leipzig: B.G. Teubner 1938,^{[6]} 2nd expanded edn. with Hans Robert Müller, Oldenbourg, München 1956
 NichtEuklidische Geometrie und Mechanik I, II, III. Leipzig: B.G.Teubner (1942)
 Zur Bewegungsgeometrie auf der Kugel. In: Sitzungsberichte der Heidelberger Akademie der Wissenschaften (1948)
 Einführung in die Differentialgeometrie. Springer 1950,^{[7]} 2nd expanded edn. with H. Reichardt 1960
 with Kurt Leichtweiß: Elementare Differentialgeometrie. Berlin: Springer (5th edn. 1973)
 Reden und Reisen eines Geometers. Berlin : VEB Deutscher Verlag der Wissenschaften (1961; 2nd expanded edn.)
 Mathematik und Leben, Wiesbaden, Steiner 1951
 Griechische und anschauliche Geometrie, Oldenbourg 1953
 Projektive Geometrie, 3rd edn, Birkhäuser 1954
 Analytische Geometrie, 2nd edn., Birkhäuser 1954
 Einführung in die Geometrie der Waben, Birkhäuser 1955^{[8]}
 Vorlesungen über Integralgeometrie, VEB, Berlin 1955
 Reden und Reisen eines Geometers, 1957
 Kinematik und Quaternionen. Berlin: VEB Deutscher Verlag der Wissenschaften (1960)
 Gesammelte Werke, Thales, Essen 1985
Namesake
A number of mathematical theorems and concepts is associated with the name of Blaschke.
 Blaschke selection theorem
 Blaschke–Lebesgue theorem
 Blaschke product
 Blaschke condition
 Blaschke–Santaló inequality
 Blaschke conjecture: "The only Wiedersehen manifolds in any dimension are the standard Euclidean spheres."
References
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} O'Connor, John J.; Robertson, Edmund F., "Wilhelm Blaschke", MacTutor History of Mathematics archive, University of St Andrews.
 ^ ^{a} ^{b} Wilhelm Blaschke at the Mathematics Genealogy Project
 ^ ^{a} ^{b} Heinrich Behnke (18981979): zwischen Mathematik und deren Didaktik, Uta Hartmann, 2009 ISBN 9783631588604
 ^ Bliss, G. A. (1923). "Blaschke on Differential Geometry". Bull. Amer. Math. Soc. 29 (7): 322–325. doi:10.1090/S000299041923037373.
 ^ Walker, R. J. (1939). "Review: W. Blaschke and G. Bol, Geometrie der Gewebe". Bull. Amer. Math. Soc. 45 (9): 652–653. doi:10.1090/s000299041939070523.
 ^ Synge, J. L. (1939). "Review: W. Blaschke, Eben Kinematik". Bull. Amer. Math. Soc. 45 (11): 814–815. doi:10.1090/s000299041939070717.
 ^ Allendoerfer, Carl B. (1951). "Review, W. Blaschke, Einführung in die Differentialgeometrie". Bull. Amer. Math. Soc. 57 (1, Part 1): 84–85. doi:10.1090/s000299041951094549.
 ^ Hsiung, C. C. (1957). "Review: W. Blaschke, Einführung in die Geometrie der Waben". Bull. Amer. Math. Soc. 63 (3): 203–204. doi:10.1090/s000299041957101049.