His principal work was in developing methods and systematic theories to analyze and solve partial differential equations, which are mathematical descriptions of the patterns of things like the movements of air and water as well as the stresses and strains on materials.
A professor emeritus at the Collège de France in Paris since 1999, Professor Lions was a former president of the French National Center of Space Studies and of the French Academy of Sciences.
In recent years he was also active as a director and scientific adviser to industry, including corporate giants like France Telecom and Dassault Systemes. He was a prolific author of books and scientific papers and was honored by universities and learned societies from all over the world. In 1991, Professor Lions won the Japan Prize, and his contributions to applied mathematics earned him the 1999 Lagrange Prize from the University of California at Berkeley. (*)
Jacques-Louis Lions was born in Grasse, in the Maritime Alps. He received his doctorate in science at the University of Paris in 1954. He taught at the University of Nancy and the University of Paris until 1972.
That year he joined the faculty of the Collège de France where he served as chairman of analysis and systems control. He was made a commander of the Legion of Honor and served as president of the Academy of Sciences in the late 1990's. He was also a member of the National Academy of Sciences in the United States.
He married Andrée Olivier in 1950. His survivors include their son, Pierre-Louis, a professor of mathematics at the University of Paris- Dauphine.
(*) Note by Francois Murat: The Lagrange Prize was founded by three Applied Mathematics Societies: Sema (Spain), Simai (Italy) and Smai (France); the University of California at Berkeley is not involved in this prize.