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The theorem was first studied in view of work on differential equations by the French mathematicians around Poincaré and Picard.
He was trained as an engineer at the École Polytechnique (entering class of 1910), served in the French Signal Corps during World War I, worked on telegraph and radio systems, and in 1926 received a doctorate in mathematics from the Sorbonne, having written a thesis on indefinite quadratic forms under the supervision of Charles Émile Picard.