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Person: De Possel, Lucien Alexandre Charles René

Lucien Alexandre Charles René de Possel was a French mathematician and computer scientist who worked on optical character recognition. He was one of the founders of the Bourbakists.

Mathematical Profile (Excerpt):

• René attended the Institution Mélizan and the Lycée at Marseille before going to Paris to study at the École Normale Supérieure.
• After completing his Agrégé de mathematique, de Possel continued to undertake research for his doctorate.
• He spent time studying at Munich, Göttingen and Berlin which had a major effect on broadening his education.
• His studies were helped financially by the award of a Rockefeller Fellowship in 1930-32 before he gained his first appointment as Maître de Conférences at the Faculty of Science at Marseille in 1933.
• He then held the same position in the Faculty of Science at Clermont-Ferrand from 1934 where he joined Szolem Mandelbrojt.
• They would go to Paris to attend the Séminaire de mathématiques in the Institut Henri-Poincaré every second Monday.
• This gave them the chance to visit bookstores and libraries as well as meet up with other friends which they had made during their studied in Paris.
• They met regularly for lunch with their friends at the Café Capoulade in boulevard Saint-Michel near the Luxembourg Gardens and it was here that he became one of the founder members of the Bourbaki group.
• In the early stages of Bourbaki, de Possel was involved on a subcommittee which considered how they would present integration theory.
• His views on integration are to be found in the expository article Les théories modernes de l'intégration Ⓣ(Modern theories of integration) which he published in 1946 and in which he sketched an abstract form of the Riemann-Stieltjes integral.
• On many issues de Possel and André Weil were on opposite sides in the arguments.
• At the first Bourbaki congress in July 1935 de Possel was still an active member of the group and much involved with contributing but, largely due to differences with Weil, he dropped out of the project.
• In 1936 he published an important book on game theory, namely Sur la théorie mathématique des jeux de hasard et de réflexion Ⓣ(On the mathematical theory of gambling and reflection).
• De Possel was appointed as professor in the Faculty of Science at Bresançon, then in 1938 professor in the Faculty of Science at Clermont.
• We look briefly at the mathematics papers which de Possel published during these year.
• In 1939 he published Sur la représentation conforme d'un domaine à connexion infinie sur un domaine à fentes parallèles Ⓣ(On the conformal representation of a connection to infinite domain on a domain with parallel divisions) in which he developed further the ideas on conformal mapping of a simply connected domain which he had published in 1931.
• In the second half of the 1940s he published a considerable number of papers.
• We mention Sur l'indétermination de la puissance d'un torseur réparti Ⓣ(On the indeterminacy of the power of a distributed couple) in which he gave proofs of some formulas of use in the mechanics of continuous media, where the differential elements are subjected to couples as well as forces per unit volume; Les principes mathématiques de la mécanique classique Ⓣ(The mathematical principles of classical mechanics) which was based in ideas due to Brelot; Sur la définition d'un torseur réparti et sur l'évaluation de sa puissance Ⓣ(On the definition of a distributed couple and the evaluation of its power) which examines when external forces on part of a body are equivalent to couples alone; Initiation à la topologie Ⓣ(Introduction to topology) resulting from work carried out in Portugal; Sur les systèmes dérivants et l'extension du théorème de Lebesgue relatif à la dérivation d'une fonction à variation bornée Ⓣ(On derived systems and the extension of the Lebesgue theorem about the derivation of a function of bounded variation) extending the classical theorem for linear Lebesgue measure; and La notion physique d'énergie vis-à-vis des définitions du travail et de la force Ⓣ(The physical concept of energy vis-à-vis the working definitions and strength) which considers the formulation of classical mechanics given by Brelot.
• De Possel worked on computer science at the Institut Blaise Pascal of the National Centre for Scientific Research, in particular working on optical character recognition.
• He continued to publish mathematics papers at during the years when he worked at the Institut Blaise Pascal: Deux lemmes sur les variétés à deux dimensions, et leur application au polygone fondamental d'une variété conforme prolongeable Ⓣ(Two lemmas on varieties in two dimensions, and their application to the fundamental polygon of a compliant extendable variety) (1962); Sur les variétés à deux dimensions, les ensembles de capacité maximale et le prolongement des variétés conformes Ⓣ(On the varieties in two dimensions, sets of maximum capacity and the extension of conformal varieties) (1964); and Sur l'existence d'ensembles d'entiers qui interviennent en théorie ergodique Ⓣ(On the existence of whole sets involved in ergodic theory) (1966).

Born 7 February 1905, Marseilles, France. Died 26 February 1974, Paris, France.

View full biography at MacTutor

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Bourbaki

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References

Adapted from other CC BY-SA 4.0 Sources:

1. O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive