Jean Gaston Darboux

Born Aug. 13, 1842, in Nîmes; died Feb. 23. 1917, in Paris. French mathematician. Member of the Paris Academy of Sciences (1884) and its permanent secretary from 1900. Corresponding member of the St. Petersburg Academy of Sciences (1895).

Darboux’s principal works are devoted to problems of differential geometry (the theory of surfaces and the theory of curvilinear coordinates): Lectures on the General Theory of Surfaces (vols. 1 -4, 1887–96) and Lectures on Orthogonal Systems and Curvilinear Coordinates (1898). His research on geometry led him to investigate various problems of integrating differential equations. Important among his works in other branches of mathematics are the memoirs on the theory of integration and the theory of analytic functions and also his research on the problem of the expansion of functions in orthogonal functions, especially in Jacobi polynomials. In mechanics, Darboux engaged in fruitful work on various problems of kinematics, equilibrium, and small fluctuations of a system of points.