Helmut Ulm

Helmut Ulm (born June 21, 1908 in Gelsenkirchen; died June 13, 1975) was a German mathematician who established the classification of countable periodic abelian groups by means of their Ulm invariants.

Helmut Ulm's father was an elementary school teacher in Elberfeld. After finishing high school in Wuppertal in 1926, he attended the universities of Göttingen (1926–1927), Jena (1927) and Bonn (1927–1930), where he studied mathematics and physics, attending the lectures of Richard Courant, , Felix Hausdorff, and the joint Hausdorff–Otto Toeplitz seminar. He graduated summa cum laude in 1930 with a thesis about countable periodic abelian groups (1933). In 1933–1935 he was an assistant in Göttingen and worked with Wilhelm Magnus and Olga Taussky-Todd editing David Hilbert's Collected Works. His Habilitationsschrift developed a generalization of the elementary divisor theory to infinite matrices, continuing ideas of Ulm's teacher Toeplitz. It was submitted in Münster in 1936 and refereed by Heinrich Behnke, Gottfried Köthe, F. K. Schmidt, and B. L. van der Waerden. Ulm's promotion was delayed, apparently, due to his anti-Nazi views.

...
Wikipedia