Charles Emile Pickard (1856-1941) French Mathematics Professor

Along with Simeon-Denis Picard was the most important and distinguished French mathematician of the day.

Piccard's Method
Pickard's method, sometimes called the method of successive approximations, gives a means of proving the existence of solutions to differential equations.

Émile Picard
Born	(1856-07-24)24 July 1856 Paris, France
Died	11 December 1941(1941-12-11) (aged 85) Paris, France
Nationality	French
Fields	Mathematics
Institutions	University of Paris
Alma mater	École Normale Supérieure
Doctoral advisor	Gaston Darboux
Doctoral students	Sergei Bernstein Lucien Blondel Gheorghe Calugareanu Paul Dubreil Jacques Hadamard Gaston Julia Traian Lalescu Philippe Le Corbeiller Paul Painlevé Mihailo Petrović Simion Stoilow Ernest Vessiot Henri Villat André Weil Stanisław Zaremba
Known for	Picard functor Picard group Picard theorem Picard variety Picard–Lefschetz formula Picard–Lindelöf theorem Painlevé transcendents
Notable awards	Fellow of the Royal Society[1]

Picard's mathematical papers, textbooks, and many popular writings exhibit an extraordinary range of interests, as well as an impressive mastery of the mathematics of his time. Modern students of complex variables are probably familiar with two of his named theorems. His lesser theorem states that every nonconstant entire function takes every value in the complex plane, with perhaps one exception. His greater theorem states that an analytic function with an essential singularity takes every value infinitely often, with perhaps one exception, in any neighborhood of the singularity. He made important contributions in the theory of differential equations, including work on Picard–Vessiot theory, Painlevé transcendents and his introduction of a kind of symmetry group for a linear differential equation. He also introduced the Picard group in the theory of algebraic surfaces, which describes the classes of algebraic curves on the surface modulo linear equivalence. In connection with his work on function theory, he was one of the first mathematicians to use the emerging ideas of algebraic topology.
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