Julius August Christoph Zech (24 February 1821 Stuttgart, Germany − 13 July 1864 Berg) was a German astronomer and mathematician.
In 1849, Zech published a table of logarithms; as a result, Zech logarithms for finite fields are named after him.
In 1863, Zech attended the founding meeting of the Astronomische Gesellschaft (German Astronomical Society) and became its Vorstand (chairman). Friedrich Wilhelm Argelander assumed this role upon Zech's death..
Julius Christian Johannes Zeller (24 June 1822, Mühlhausen am Neckar – 31 May 1899, Cannstatt) was a German mathematician. He was born to Gottlob Zeller and Christiana Friedrike Moser.Originally trained in mathematics, geography and theology, in 1874 Zeller became Director of the Seminary in Markgröningen and a girls' orphanage. In 1882 he became a member of the Société Mathématique de France. The following year, on 16 March 1883, he delivered a short account of his congruence relation (Zeller's congruence), which was published in the society's journal.
He was later awarded the Order of Friedrich, First Class, and the Ritterkreuz of Württemberg. He retired in 1898, and died in the following summer.
Ernst Erich Jacobsthal (16 October 1882, Berlin – 6 February 1965, Überlingen) was a German mathematician, and brother to the archaeologist Paul Jacobsthal.
In 1906, he earned his PhD at the University of Berlin, where he was a student of Georg Frobenius, Hermann Schwarz and Issai Schur; his dissertation, Anwendung einer Formel aus der Theorie der quadratischen Reste (Application of a Formula from the Theory of Quadratic Residues), provided a proof that prime numbers of the form 4n + 1 are the sum of two square numbers. In 1934, he was fired from his professorship at the Technische Hochschule Berlin, because of his Jewish origins. In 1939 he fled to Norway and became after the war a professor at the Norwegian Institute of Technology in Trondheim.
Hans Ludwig Hamburger (5 August 1889, Berlin – 14 August 1956, Cologne) was a German mathematician. He was a professor at universities in Berlin, Cologne and Ankara.
Erich Bessel-Hagen (12 September 1898 in Charlottenburg – 29 March 1946 in Bonn) was a German mathematician and a historian of mathematics.Erich Paul Werner Bessel-Hagen was born in 1898 in Charlottenburg, a suburb, later a district in Berlin. He studied at the University of Berlin where in 1920 he obtained a Ph.D. in mathematics under the direction of Constantin Carathéodory.
His reputation was that of a gentleman as well as a conscientious intellect. This was averred in the early 1940s, when the ruling Nazis increased their persecutions of German officials who have Jewish ancestry. After Felix Hausdorff (a professor 30 years his senior) had been retired and placed under restrictions, Bessel-Hagen became the only former colleague who visited him regularly. On noticing that Hausdorff used private math researches to while away time, he started bringing him books he had borrowed from a library which no longer welcomed Jews.
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.
Gerhard Hessenberg (German: [ˈgɛʁ.hart ˈhɛsənˌbɛrk]; 16 August 1874 – 16 November 1925) was a German mathematician who worked in projective geometry, differential geometry, and set theory.
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.
Oskar Perron (7 May 1880 – 22 February 1975) was a German mathematician.
He was a professor at the University of Heidelberg from 1914 to 1922 and at the University of Munich from 1922 to 1951. He made numerous contributions to differential equations and partial differential equations, including the Perron method to solve the Dirichlet problem for elliptic partial differential equations. He wrote an encyclopedic book on continued fractions Die Lehre von den Kettenbrüchen. He introduced Perron's paradox to illustrate the danger of assuming that the solution of an optimization problem exists:
Let N be the largest positive integer. If N > 1, then N2 > N, contradicting the definition of N. Hence N = 1.