Otto Stolz

Who was Otto Stolz?

Otto Stolz was an Austrian mathematician noted for his work on mathematical analysis and infinitesimals. Born in Hall in Tirol, he studied in Innsbruck from 1860 and in Vienna from 1863, receiving his habilitation there in 1867. Two years later he studied in Berlin under Karl Weierstrass, Ernst Kummer and Leopold Kronecker, and in 1871 heard lectures in Göttingen by Alfred Clebsch and Felix Klein, before returning to Innsbruck permanently as a professor of mathematics.

His work began with geometry but after the influence of Weierstrass it shifted to real analysis, and many small useful theorems are credited to him. For example, he proved that a continuous function f on a closed interval [a, b] with midpoint convexity, i.e., has left and right derivatives at each point in.

He died in 1905 shortly after finishing work on Einleitung in die Funktionentheorie. His name lives on in the Stolz-Cesàro theorem.