Professor at "Collège de France", member and past Vice-President and President of the French Academy of Sciences, member, among several others, of the Brazilian Academy of Sciences, past President of the International Mathematic Union from 1990 to 1994, Jacques- Louis Lions was born in Grasse, France on May 2nd, 1928 and died in Paris on May 17, 2001.
I got in contact with him for the first time in 1965 when I was working with Felix E. Browder in the United States on nonlinear hyperbolic partial differential equations. At that time, motivated in part by the fundamental contributions by Konrad Jörgens, Felix E. Browder and Irving Segal, that was a flowering research field. Simultaneously, Jacques-Louis Lions and Walter A. Strauss were also developing independently mathematical methods for boundary value problems for nonlinear hyperbolic partial differential equations. In October 27, 1965, he sent me a letter: "Browder showed me a pre-print of your paper on nonlinear wave equations. Could you kindly send me a copy of it, if available?", see [32]. That became the starting point a strong friendship that lasted for 36 years.
By that time I had already read his fascinating paper in which he applied Functional Analysis and Schwartz’s distributions to investigate boundary value problems for partial differential equations. That was precisely the mathematics I wanted to do.
From then on, we frequently exchanged letters on mathematical problems and also about the organization and orientation of Mathematics.
In 1971/72, with the support of Laurent Schwartz and Leopoldo Nachbin, I had the chance of visiting the "Laboratoire d’Analyse Numérique de l’Université de Paris VI", with a scholarship of the French Government. Lions was the Chairman of the Laboratoire at that time and I had the opportunity of meeting him personally and to attend his lectures in Jussieu. The first day I met him he introduced me to E. Magenes and offered me his book on "Les Inéquations en Mécanique et en Physique", in collaboration with G. Duvaut.