Cauchy , Baron Augustin Louis

(1789–1857) French mathematician

Cauchy showed great mathematical talent at an early age and came to the attention of Joseph Lagrange and Pierre Laplace, who encouraged him in his studies. Born in Paris, France, he was educated at the Ecole Polytechnique, where he later lectured and became professor of mechanics in 1816, and worked briefly as an engineer in Napoleon's army. He held extreme conservative views in religion and politics, typical of which was the strong allegiance to the Bourbon dynasty that caused him to follow Charles X (who had ennobled Cauchy) into exile in 1830. Cauchy then became professor of mathematics at Turin, but returned to France in 1838 and resumed his post at the Ecole Polytechnique.

Cauchy was an extremely prolific mathematician who made outstanding contributions to many branches of the subject, ranging from pure algebra and analysis to mathematical physics and astronomy. He was also an outstanding teacher. His greatest achievements were in the fields of real and complex analysis in which he was one of the first mathematicians to insist on the high standards of rigor now taken for granted in mathematics. He gave the first fully satisfactory definitions of the fundamentally important concepts of limit and convergence.