(1871-1956) French mathematician who rationalized the theory of functions of real variables.
Borel was born in St-Affrique and studied in Paris. In 1893 he was appointed to the faculty of mathematics at the University of Lille. The Sorbonne created a chair in function theory for him, which he held 1909–40. From 1910 he was also in charge of science at the Ecole Normale Supérieure. He was a Radical-Socialist member of the national chamber of deputies 1924–36, serving as minister of the navy 1925.
In the 1890s Borel did his most important work: on probability, infinitesimal calculus, divergent series, and, most influential of all, the theory of measure. He provided a proof of Charles Emile Picard's theorem 1896. In the 1920s he wrote on the subject of game theory, before John Von Neumann (generally credited with being the founder of the subject) first wrote on it in 1928. Borel's theory of integral functions and his analysis of measure theory and divergent series established him, alongside French mathematician Henri Lebesgue, as one of the founders of the theory of functions of real variables.