Augustin-Louis Cauchy
1789–1857, Paris, France, Sceaux, near Paris, France
French mathematician who put analysis on a rigorous footing, pioneering the modern theory of limits, convergence and complex functions, and produced more mathematical papers than anyone before him.
Cauchy grew up in Paris during the turbulence of the Revolution; Lagrange and Laplace were family friends who took an early interest in his mathematical education. He trained as an engineer at the École Polytechnique and École des Ponts et Chaussées before turning fully to mathematics, becoming assistant professor of analysis at the École Polytechnique in 1816 and a member of the Academy of Sciences the same year.
Cauchy's 1821 textbook Cours d'analyse gave the first rigorous treatment of limits, continuity and convergence of series, reshaping calculus into modern analysis. He founded the theory of functions of a complex variable, proving the Cauchy integral theorem and Cauchy integral formula, and his name is attached to the Cauchy–Schwarz inequality, Cauchy sequences and the Cauchy–Riemann equations. A devout Catholic, he refused to swear allegiance to the July Monarchy in 1830 and spent years in exile teaching in Turin and Prague before returning to Paris in 1838. He wrote 789 mathematical papers, an output unmatched in his era, and died near Paris in 1857.
Workplaces: École Polytechnique, Paris, Collège de France, Paris, University of Turin
France