GUSTAVE CHOQUET

Gustave Choquet, who was the Hardy Lecturer of the London Mathematical Society in 1969 and elected an Honorary Member of the Society in 1988, died on 14 November 2006, aged 91. He was born in Solesmes in north-eastern France on 1 March 1915, studied at the École Normale Supérieure 1934–38, and succeeded brilliantly in the mathematical Agrégation in 1937. Embarking on research, he received guidance and much encouragement from Denjoy. A Jane Eliza Proctor bursary allowed him to visit Princeton for the year 1938–39. During the war he continued research with the support of the CNRS, and he obtained his Docteur es Sciences degree in 1946. He taught at the French Institute in Poland 1946–47. After a brief spell as Maître de Conférences, he was Professor in the University of Paris (later in Paris VI) 1950–1984; he was also Professor at the Ecole Polytechnique, 1965–70. He was a Member of the Académie des Sciences, and an Officer of the Légion d’Honneur.

He published more than 160 mathematical articles and 11 books. He made important contributions to a variety of fields: topology, measure theory, descriptive set theory, potential theory, and functional analysis. Two themes deserve particular mention. His monumental 1953/4 paper Theory of capacities contains among many riches his celebrated capacitability theorem. A second great theme is his theory of integral representations in compact convex sets and weakly complete cones, now usually known as Choquet theory, which launched a huge development. The work on capacities and that on integral representations have both found many applications in analysis and probability.

His personal distinction was allied in a remarkable way to great kindness and humanity. He was an inspiring teacher who gave generous encouragement and support to pupils and younger colleagues. The Équipe d'Analyse which he founded remains active today. For many years he collaborated with Brelot and Deny in running a seminar on potential theory. He also founded in 1960 the Séminaire de l’Initiation à l'Analyse, which still meets regularly. He was President of the International Commission for the Study and Improvement of Mathematical Teaching, 1950–62.

His leisure pursuits included gardening and mountain walking, and he was devoted to his family. His wife Madame Yvonne Choquet-Bruhat, who survives him, is herself a distinguished mathematician and a Member of the Académie des Sciences.

D.A. Edwards
University of Oxford