Cauchy, Augustin Louis, Baron[kohshee]
Mathematician, born in Paris, France. He studied to become an engineer, but ill health forced him to retire and teach mathematics at the Ecole Polytechnique. He did important work on partial differential equations, the wave theory of light, and the mathematical theory of elasticity, but is primarily remembered as the founder of the theory of functions of a complex variable. In algebra he gave a definitive account of the theory of determinants, and developed the ideas of group theory.