One of the greatest experts in probability theory in history. He was born and educated in Zagreb, where he started his university study of mathematics, a professor at the Universities of Kiel, Copenhagen, Stockholm, Lund, Providence, Princeton etc., a member of many scientific organizations. Many important mathematical notions bear his name: Feller's process, Feller's transition function, Feller's semigroup, Feller's property.
William Feller, 100 years since the birth of outstanding mathematician