Education
In 1906, he earned his Doctor of Philosophy 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 Remainders), provided a proof that prime numbers of the form 4n + 1 are the sum of two square numbers.
