Borel, Emile (1871–1956)
French mathematician who worked on divergent series, the
theory of functions, probability, and game
theory, and was the first to define games of strategy. He also founded
measure theory, which applies the
theory of sets to the theory of functions, and thus became an originator,
with Henri Lebesgue and René Louis Baire
(1874–1932), of the modern theory of functions of a real variable.