Ernst Hellinger

Ernst David Hellinger ( born September 30, 1883 in Striegau (now Poland), † March 28, 1950 in Chicago ) was a German mathematician.

Ernst Hellinger studied mathematics at the universities of Heidelberg, Breslau and Göttingen with David Hilbert. During her studies, he became friends with Max Born. In his doctoral thesis of 1907, he developed a new type of integral, the so-called Hellinger integral. Later, he developed together with the Hilbert Hilbert - Hellinger theory. In 1914 he became a professor in Frankfurt.

In 1936, he was transferred as a Jew by the Nazis into forced retirement. Even after Kristallnacht in 1938, he refused to flee and was arrested on November 13 and deported to the concentration camp at Dachau. After intercession of influential friends, he was released after six weeks from the concentration camp, under the condition that he would emigrate. In February 1939 Hellinger traveled to the United States.

He worked there until his death in 1950 in the field of integral calculus and spectral theory. His article integral equations and equations with infinitely many unknowns from 1927 is a classic of the area of integral equations. The set of Hellinger - Toeplitz is associated with his name.