Helmut Hasse (German: [ˈhasə]; 25 August 1898 – 26 December 1979) was a German mathematician working in algebraic number theory, known for fundamental contributions to class field theory, the application of p-adic numbers to local class field theory and diophantine geometry (Hasse principle), and to local zeta functions.
Karl Menninger (October 6, 1898 – October 2, 1963) was a German teacher of and writer about mathematics. His major work was Zahlwort und Ziffer (1934,; English trans., Number Words and Number Symbols), about non-academic mathematics in much of the world. (The omission of Africa was rectified by Claudia Zaslavsky in her book Africa Counts.)
Ludwig Otto Blumenthal (20 July 1876 – 12 November 1944) was a German mathematician and professor at RWTH Aachen University.
Paul Epstein (July 24, 1871 – August 11, 1939) was a German mathematician. He was known for his contributions to number theory, in particular the Epstein zeta function.
Epstein was born and brought up in Frankfurt, where his father was a professor. He received his PhD in 1895 from the University of Strasbourg. From 1895 to 1918 he was a Privatdozent at the University in Strasbourg, which at that time was part of the German Empire. At the end of World War I the city of Strasbourg reverted to France, and Epstein, being German, had to return to Frankfurt.
Epstein was appointed to a non-tenured post at the university and he lectured in Frankfurt from 1919. Later he was appointed professor at Frankfurt. However, after the Nazis came to power in Germany he lost his university position. Because of his age (68) he was unable to find a new position abroad, and finally committed suicide by barbital overdose at Dornbusch, fearing Gestapo torture because he was a Jew.
Charles-Jean Étienne Gustave Nicolas, baron de la Vallée Poussin (French pronunciation: [ʃaʁl ʒɑ̃ etjɛn ɡystav nikɔla baʁɔ̃ də la vale pusɛ̃]; 14 August 1866 – 2 March 1962) was a Belgian mathematician. He is best known for proving the prime number theorem.
The King of Belgium ennobled him with the title of baron.
Joseph Marie de Tilly (16 August 1837 – 4 August 1906) was a Belgian military man and mathematician.
He was born in Ypres, Belgium. In 1858, he became a teacher in mathematics at the regimental school. He began with studying geometry, particularly Euclid's fifth postulate and non-Euclidean geometry. He found similar results as Lobachevsky in 1860, but the Russian mathematician was already dead at that time. Tilly is more known for his work on non-Euclidean mechanics, as he was the one who invented it. He worked thus alone on this topic until a French mathematician, Jules Hoüel, showed interest in that field. Tilly also wrote on military science and history of mathematics. He died in München, Germany.
Jules Tannery (24 March 1848 – 11 December 1910) was a French mathematician, who notably studied under Charles Hermite and was the PhD advisor of Jacques Hadamard. Tannery's theorem on interchange of limits and series is named after him. He was a brother of the mathematician and historian of science Paul Tannery.
Under Hermite, he received a doctorate in 1874 for his thesis Propriétés des intégrales des équations différentielles linéaires à coefficients variables.
Tannery was an advocate for mathematics education, particular as a means to train children in logical consequence through synthetic geometry and mathematical proofs.Tannery discovered a surface of the fourth order of which all the geodesic lines are algebraic. He was not an inventor, however, but essentially a critic and methodologist. He once remarked, "Mathematicians are so used to their symbols and have so much fun playing with them, that it is sometimes necessary to take their toys away from them in order to oblige them to think."
He notably influenced Pierre Duhem, Paul Painlevé, Jules Drach, and Émile Borel to take up science.
His efforts were mainly directed to the study of the mathematical foundations and of the philosophical ideas implied in mathematical thinking.
Tannery was "an original thinker, a successful teacher, and a writer endowed with an unusually clear, brilliant and attractive style."
