Friedrich Hartogs

Friedrich Moritz Hartogs, known as Fritz (1874-1943), was a mathematician from a German-Jewish family, born in Brussels and brought up in Frankfurt am Main. He studied at Hanover, Berlin and Munich and took his doctorate at the University of Munich in 1903 under Alfred Pringsheim, habilitating in 1905 and spending his career there, becoming a full professor in 1927. He is remembered for foundational results on functions of several complex variables, including Hartogs theorem on removable compact singularities of holomorphic functions, the Hartogs lemma and the ideas of holomorphic hull and domain of holomorphy. In set theory he proved that for every set there is a well-ordered set that cannot be injectively embedded in it, which gives the Hartogs number. Forced from his chair in 1935 because he was Jewish and held briefly in Dachau in 1938, he died in Munich in 1943.