Hellinger, Ernst, 1883-

Ernst Hellinger was born in Striegau, Silesia, on September 30, 1883. After studying at the University of Heidelberg and the University of Breslau, Hellinger took his PhD in mathematics at the University of Gottingen (where he worked with David Hilbert and Franz Klein) in 1907. Hellinger studied integral equations, infinite systems of equations, real functions, and continued fractions.

Hellinger taught at Gottingen (1907-1909), Marburg (1909-1914), and Frankfurt (1914-1935). The Nazis removed him from the faculty at Frankfurt in 1936. He joined the faculty at Northwestern as lecturer in Mathematics in 1939. He became a U.S. citizen in 1944. Promoted to professor in 1945, Hellinger became emeritus in 1949. He died March 28, 1950, in Chicago.

Hellinger studied integral equations, infinite systems of equations, real functions, and continued fractions. A type of integral he introduced in his dissertation became known as “the Hellinger integral” and the Hilbert-Hellinger theory of forms in infinitely many variables profoundly influenced mathematical analysis.

From the guide to the Ernst D. Hellinger (1883-1950) Papers, 1906-1975, (Northwestern University Archives)