**Paul Dubreil** was a French mathematician who worked in algebraic geometry. He was married to fellow mathematician Marie-Louise Dubreil-Jacotin.

- These were difficult times for the young Dubreil who was fourteen years old when the war ended.
- Graduating from the lycée Montesquieu in 1921, Dubreil went to Paris where he studied at the Lycée St Louis, preparing for the entrance examinations to one of the École Normale Supérieure or the École Polytechnique.
- Not only did Dubreil have outstanding teachers at the École Normale Supérieure, but he also had some excellent mathematicians as fellow students including René de Possel and Pierre Honnorat.
- In 1924-25 Dubreil attended the Cours Peccot delivered at the Collège de France by Marcel Légaut (1900-1990) on Étude géométrique des systèmes de points dans un plan.
- Dubreil also read Légaut's 1926 translation into French of Courbes et fonctions algébraiques d'une variable Ⓣ(Curves and algebraic functions of one variable) by Federigo Enriques.
- In the 1926 Agrégation de Mathématiques, a national examination to find the best candidates for teaching positions, Dubreil was placed first in the whole of France.
- After the lectures, Artin would return to the Institute followed by his students, including Dubreil, and after chatting until around 14:00, they all went with Artin to a nearby restaurant.
- Dubreil got to know her at the lunch, then he attended her lecture in the evening which was given in the main lecture theatre to an audience of philosophers and mathematicians.
- Dubreil, however, found discussions with her extremely useful.
- Then he went to Frankfurt because by that time Noether was in Frankfurt for the summer semester, visiting Carl Siegel, and Dubreil wanted to continue exchanging ideas with her.
- In Frankfurt, Dubreil also met Max Dehn and his students Wilhelm Magnus and Ruth Moufang.
- Dubreil returned to Paris briefly to defend his doctoral thesis Recherches sur la valeur des exposants des composants primaires des ideaux de polynomes Ⓣ(Research on the value of the exponents of the primary components of the ideals of polynomials) in October 1930.
- Certainly Dubreil was going to get the most out of his Rockefeller scholarship and he next went to Rome where he discussed problems with the geometers Guido Castelnuovo, Federigo Enriques and Francesco Severi.
- While in Rome, Dubreil was invited to a dinner given by Levi-Civita in honour of Solomon Lefschetz who, along with his wife, was spending a sabbatical year in Europe.
- Dubreil's main interest at that time was algebraic varieties and he believed that he had learnt most from Noether so, before returning to France, his final visit was again to Göttingen to visit Noether.
- Once there, he met Lars Ahlfors who, like Dubreil, was supported with a Rockefeller scholarship.
- Herbrand's accident was reported in Le Temps on 29 July 1931 and a cutting from the paper sent to Dubreil in Göttingen.
- He told Emmy Noether what had happened and she was deeply saddened and kept repeating, "That is unthinkable." While in Göttingen, Dubreil joined in the traditional walk after the Seminar in the wooded hills east of the city.
- The exciting travels of his fellowship over, Dubreil took up his first permanent post at the University of Lille.
- In November 1946 Dubreil returned to the Sorbonne and there, in October 1954, he was appointed to the chair of arithmetic and number theory.
- After his Ph.D. thesis, Dubreil published a series of papers: Recherches sur la valeur des exposants des composants primaires des idéaux de polynomes Ⓣ(Research on the value of the exponents of the primary components of the ideals of polynomials) (1930); Sur quelques propriétés des systèmes de points dans le plan et des courbes gauches algébriques Ⓣ(On some properties of systems of points in the plane and algebraic space curves) (1933); Sur les intersections totales mixtes dans l'espace à trois dimensions Ⓣ(On the total mixed intersections in three-dimensional space) (1933); Sur quelques propriétés des variétés algébriques Ⓣ(On some properties of algebraic varieties) (1934); and Quelques propriétés des variétés algébriques se rattachant aux théories de l'algèbre moderne Ⓣ(Some properties of algebraic varieties pertaining to the theories of modern algebra) (1935).
- Anatoly Malcev, Alfred Clifford and Dubreil became major figures in the new subject.
- He was directing a large number of theses, and the weekly meetings of the Dubreil-Pisot seminar were rallying points of researchers, coming even from distant universities to listen to a very wide variety of guest lectures.
- In 1946 Dubreil published his book Algèbre.

Born 1 March 1904, Le Mans, Maine, France. Died 9 March 1994, Soisy sur École (near Paris), France.

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Bourbaki

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