Laurent Schwartz , born on March 5th, 1915 with Paris and dead on July 4th, 2002 in Paris, is one of large the Mathématicien S French of the 20th century. After having been raises with the National university, it obtained the Médaille Fields in 1950 for its work on the theory of the distributions. It was during many years professor with the Polytechnic school.
It was also distinguished in the history by its many political combats.
It was in addition impassioned of Entomologie, more precisely of the butterflies, of which it constituted a vast collection.
Biography
Family
Laurent Schwartz is resulting from an Jewish family of Alsatian origin, impregnated of scientific culture: his/her father is a Chirurgie famous N, his uncle, Robert Debré (founder of UNICEF) is famous a Pédiatre, his great-uncle by alliance, Jacques Hadamard is a famous mathematician. His/her brother, Bertrand Schwartz, directed the école des Mines of Nancy and contributed to the creation of the local missions for the employment of the young people.
During the preparation to the entrance examination to the National university, which it carries out with the Louis-the-Large Lycée, it falls in love with Marie-Helene Levy, the girl of the probabilist Paul Levy who was then professor with the Polytechnic school. They had two children: Marc Andre Schwartz, a poet and writer who committed suicide in 1971 and Claudine who Maria with Raoul Robert.
His/her mother, impassioned by the natural science transmits to him her taste for the Entomologie. It will cultivate this passion all its life and more particularly for the butterflies. Its personal collection, bequeathed to the national Natural history museum of natural history, with the Museum of Lyon, the Museum of Toulouse and the Museum of Cochabamba (Bolivia) comprised about 20 000 specimens, collected during its various voyages. Several species even were discovered by him, and bear its name.
Schooling
Opinion of its professors, the schooling of Laurent Schwartz is brilliant. He excels in Latin, Greek and mathematics. Its professor of 5th said to his parents: “Be wary, one will say that your son is gifted for the languages, whereas it is interested only in the scientific and mathematical aspect languages: it is necessary that he becomes mathematician”. In 1934, it enters to the National university and successfully passes the aggregation of mathematics in 1937, received second.
Higher learning
After having left the ENS with very good performances, it leaves to achieve its military service (two years 1937-1939) as officer. This service is prolonged of one year an active service during the war (1939-1940). He became then reserve officer. Demobilized in August 1940, Schwartz goes to Toulouse where his/her parents live. His/her father, who is then colonel of reserve of the medical department of the armies, works as surgeon at the hospital. Schwartz at that time becomes member of the National bank of sciences (old CNRS). A purse financed by Michelin enables him to live of 1943 until the end of the war. The chance intervenes then to save it scientific desert in which he lives: Henri Cartan comes to Toulouse to make pass from the oral examinations of entry to the ENS. Marie Helene which had translated a few years earlier of work of Cartan, takes the initiative to meet it. This last strongly invites them to move for the faculty of Clermont-Ferrand, which is then twinned with that of Strasbourg. The change was very beneficial. It was in Clermont that it met André Weil and will be integrated into the group of mathematicians “Nicolas Bourbaki”. The latter stimulated it sufficiently so that it finishes its thesis of Doctorat in two years. In 1943, it supports its thesis “Study of the sums the exponential ones”.
During the Second world war
The life of Schwartz during the Second world war “is very animated”. Jewish, it must hide and change identity to avoid the Déportation, but it discovers the world of mathematical research and begins its thesis in Clermont-Ferrand, where the university of Strasbourg is delocalized. While its research progresses, the war beats full sound. Its fragile health prevents it from joining resistance. The inefficiency of the movement trotskist fills it of frustration. Two students finish their thesis at the same time as Schwartz with Clermont: Felbau, a student of Ehresmann and Gorny, a political refugee who worked with Benoît Mandelbrot. Feldau was off-set in Auschwitz in November 1943 and Gorny with Drancy. They are never revived. Schwartz risked the deportation because of its Jewish origins and as trotskist. The couple had to adopt a false identity (with Protestant consonance: Laurent-Marie Sélimartin in the place of Laurent-Brace Schwartz and Marie-Helene Lengé) and had to hide sufficiently to escape the Nazis.
University career
After one year with Grenoble (1944), Schwartz joined the university of Nancy (1945) on the initiative of Delsarte and Dieudonné. It will remain during seven years on this station, prolific at the same time on the level of research but also on the level of the courses. The courses of Laurent Schwartz attract thus students like B. Malgrange, J.L. Lions, F. Bruhat and A. Grothendieck. On the initiative of Denjoy, it passes from Nancy to the Faculty of Science of the Université of Paris in 1952. In 1958, he becomes professor with the Polytechnic school. Having first of all refused to aspire to this station, it changes opinion at the last time, moved by its desire of recasting of mathematical Polytechnique teaching. It however was interdict of teaching there, of 1961 to 1963 after having signed the Manifeste of the 121, little appreciated gesture of the military framing of this institution. It modernizes the programs there and designs a mathematical research center there. He is elected corresponding Academy of Science on May 2nd, 1973, then member on February 24th, 1975, mathematical section.
Activities
Contributions in mathematics
August 30th, 1950, Harald Bohr introduces Laurent Schwartz for the Médaille Fields (the equivalent of the Nobel Prize in mathematics) to the international congress of Harvard for its work on the distributions. He was then the first French to receive this reward. Schwartz will have many difficulties to go to the the United States to receive this medal because of its past trotskist. Its theory clarifies the mysteries of the Fonction of Heaviside like those of the Fonction Delta of Dirac. It opens the doors of the theory of the transformed of Fourier and becomes of an major importance for the study of the partial derivative equations. In the field of the mathematical Analysis, the distributions generalize the functions and the measurement S. They make it possible to give a Dérivée (in a certain direction) to functions which, in the usual sense, are not derivable. The distributions made it possible to unify and solve a certain number of problems in Mathématiques, Physique, and even in electronic. They made it possible for example to give a direction to the “function” delta of Dirac, null except into 0, and yet of integral equalizes to 1, (in fact, it is about a measurement), and to explain why it is the derivative of the function in staircase being worth (- 1/2) on