Haïm Brezis, one of the leading figures in 20th century mathematics, died on 7 July. Born in Riom-ès-Montagnes, France, on 1 June 1944, Brezis combined mathematical analysis with the study of differential equations in an exceptional way. He began his career in pure mathematics under G. Choquet and J.-L. Lions, and then turned to practical applications.
Brezis was a pioneer in functional analysis applied to non-linear partial differential equations (PDEs), an area in which he established methods that became fundamental. He supervised 58 doctoral theses and had a significant influence on mathematicians around the world, including Fields Medal winners.
Among his most outstanding contributions were the concepts of monotone maximal operators, nonlinear semigroups of contractions and variational inequalities. His 1973 book on monotone maximal operators is an essential work in the field. He also made important contributions to the modelling of nuclear fusion plasmas, superconductivity and liquid crystals.
He taught at the University of Paris VI and at universities in the United States and Israel, and played a crucial role in the training of young Spanish mathematicians. His academic legacy and his numerous international collaborations have left a lasting mark.
To read the full obituary written by Professors J. I. Díaz and J. L. Vázquez, click here.