Augustin-Louis Cauchy (1789-1857)

Augustin-Louis Cauchy received a formal religious education in Paris, and held outspoken religious convictions for which he was often criticized. Neils Abel once referred to him as "mad" but admitted that his breadth of knowledge in mathematics was vast. As a young man, Cauchy worked as an engineer, but his mathematical ability was so strong that it is said that Leibniz encouraged him to leave engineering for a career as a mathematician. Cauchy's personal, academic, and professional life were intertwined with political movements of the time; as a child, he suffered hunger as a result of scarcities brought about by the French Revolution. In 1830, his refusal to swear an oath of loyalty to the incumbent regime cost him his academic appointment. In 1848 he regained his position following the overthrow of the government. Cauchy was extremely prolific, publishing nearly eight hundred papers in his career, in topics ranging from differential and partial differential equations, applied physics, complex functions, and theory of determinants. Many important theorems are attributed to him, including the familiar mean-value theorem. He is closely linked with Gauss, having spent much of his time expanding Gauss's earlier work. Cauchy's collected works are available, and fill a twenty-seven-volume set.