Zermelo, Ernst
(Friedrich Ferdinand), 1871-, German mathematician. Professor of mathematics at Zurich, 1910-1916, and at Freiburg, 1926-. His important contributions to the foundations of mathematics are the Zermelo axiomatic set theory (see logic, formal, 9), and the explicit enunciation of the axiom of choice (q.v.) and proof of its equivalence to the proposition that every class cm be well-ordered. — A.C.