The Jacques-Louis Lions Laboratory celebrated its fortieth anniversary in 2009, but its origins date back to 1946, when Joseph Pérès, a scientist working in mechanics, was commissioned by the CNRS to create a structure that should guide research in several directions, including translation automatic control and the implementation of the means of scientific calculation essential to French research. This is how the Blaise Pascal Institute was born, a large part of which will be located in Paris in the 19th arrondissement, rue du Maroc, the premises are those of a former chocolate factory. Following various research orientations and the scientific interests of the various directors, linguists, logicians, mathematicians, future computer scientists were welcomed in this institute.

René de Possel was appointed Professor to the Numerical Analysis Chair of the Faculty of Sciences of Paris in 1957, when he returned from Algeria. He also began to manage the Blaise Pascal Institute, thus replacing Louis Couffignal who had not succeeded in developing modern computing tools. René de Possel was an original and open-minded mathematician, one of the founders of the Bourbaki group. He was interested in various areas of pure and applied mathematics and welcomed researchers from different disciplines to the Institute. And it was thus that Jacques-Louis Lions arrived at the Blaise Pascal Institute from Nancy in 1962 and was appointed Professor to the Numerical Analysis Chair, succeeding René de Possel.

Jacques-Louis Lions quickly formed a small team of academics and researchers interested in differential equations, partial differential equations, and the approximate computation of their solutions. Several groups were formed within the Blaise Pascal Institute. For instance, the numerical analysts gathered in an Associate Research Team which formed the core of the future Numerical Analysis Laboratory. At the same time, the computer scientists created the Institute of Programming that later became the Laboratory of Computer Science of the University of Paris VI (now Sorbonne University).

The Numerical Analysis Laboratory was established in 1969 under the direction of Jacques-Louis Lions when he moved along with his team of about twenty members in new premises located on the 5th floor of the Tower 55-65 on the Jussieu campus. The Laboratory developed very quickly. Within a few years, the number of its members grew from twenty to fifty, its activities diversified and many fields of mathematics began to be represented in both research and teaching.

Jacques-Louis Lions was elected at the Collège de France in 1972 and shortly after at the Académie des Sciences. He then handed the Laboratory management over to one of his former students, Pierre-Arnaud Raviart.

French version : G. Tronel

February 2014.