Jacques Hadamard 
Lectures on Cauchy’s Problem in Linear Partial Differential Equations [EPUB ebook] 

Would well repay study by most theoretical physicists.‘ —
Physics Today

‚An overwhelming influence on subsequent work on the wave equation.‘ —
Science Progress

‚One of the classical treatises on hyperbolic equations.‘ —
Royal Naval Scientific Service

Delivered at Columbia University and the Universities of Rome and Zürich, these lectures represent a pioneering investigation. Jacques Hadamard based his research on prior studies by Riemann, Kirchhoff, and Volterra. He extended and improved Volterra’s work, applying its theories relating to spherical and cylindrical waves to all normal hyperbolic equations instead of only to one. Topics include the general properties of Cauchy’s problem, the fundamental formula and the elementary solution, equations with an odd number of independent variables, and equations with an even number of independent variables and the method of descent.