Sur la découverte des multiplicateurs de Lagrange

Lien vers la page Web de l'orateur Résumé : The talk explains how

• - a thick book on mechanics (Varignon 1725),
• - a letter by Johann Bernoulli to Varignon (1715),
• - Euler's Methodus (1744, on variational calculus),
• - and d'Alembert's Dynamique from 1743,

led to the famous Mécanique analytique (1788, 1811) by Lagrange, in which, in the first part, the advantage of the methods of multipliers is demonstrated at many examples and, in the second part, the equations of Lagrange dynamics are derived from the principle of least action. In the third part of the talk we extend the ideas of Euler and Lagrange to the problems of optimal control (Caratéodory, Hestenes, Bellman, Pontryagin).