Cauchy, Augustin Louis, Baron (ōgüstăNˈ lwē bärôNˈ kōshēˈ) [key], 1789–1857, French mathematician. He was professor simultaneously (1816–30) at the École polytechnique, the Sorbonne, and the Collège de France in Paris. While a political exile (1830–38) he taught at the Univ. of Turin. He returned to the Sorbonne in 1848. Besides his influential work in every branch of mathematics (especially the theory of functions, integral and differential calculus, and algebraic analysis) he contributed to astronomy, optics, hydrodynamics, and other fields. Among his nearly 800 publications are works on the theory of waves (1815), algebraic analysis (1821), elasticity (1822), infinitesimal calculus (1823, 1826–28), differential calculus (1827), and the dispersion of light (1836).