Henri Léon Lebesgue

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Henri Léon Lebesgue
Henri Léon Lebesgue

Henri Léon Lebesgue [ ɑ̃ʁiː leɔ̃ ləˈbɛg ] (born June 28, 1875 in Beauvais , † July 26, 1941 in Paris ) was a French mathematician .

He expanded the concept of integral and thus founded the theory of measure . The Lebesgue measure and the Lebesgue integral are named after him . The Lebesgue measure generalized the measures previously used (like the Jordan measure ) and, like the corresponding Lebesgue integral, soon became the standard tool in real analysis .

Life

He lost his father, a typesetter , to tuberculosis at an early age, and it was only thanks to the support of his hard-working mother that he was able to attend high schools, where he received excellent grades. He studied from 1894 to 1897 at the École normal supérieure and taught from 1899–1902 as a high school teacher in Nancy. There he also succeeded in discovering the integral named after him ( Sur une généralisation de l'intégrale définie , Comptes Rendus 1901). After he also received his doctorate in 1902 ( Intégrale, Longueur, Aire , Annali di Mathematica), he received his first university position in Rennes . In 1906 he received a professorship for mechanics in Poitiers . In recognition of his achievements, he was already holding courses at the Collège de France , from which the books Leçons sur l'intégration et la recherche des fonctions primitives (1904) and Leçons sur les séries trigonométriques (1906) emerged. In 1910 he received an assistant position at the Sorbonne , where he became a professor in 1918. From 1921 he became a professor at the Collège de France. In 1922 he became a member of the Académie des Sciences .

He was married from 1903 to 1916 and had two children. The lunar crater Lebesgue and the asteroid (26908) Lebesgue are named after him. In 1919 he was president of the Société Mathématique de France .

Services

Leçons sur l'integration et la recherche des fonctions primitives , 1904

The importance of Lebesgue's ideas is that his integration theory (that of the Lebesgue integral) has a number of useful properties that the Riemann integral lacked (such as completeness ). He wrote many of the fundamental sentences in this area, for example the Lebesgue sentence . In addition to his integration theory, he also worked on Fourier series , potential theory and other problems in analysis . He also dealt with geometry and the history of mathematics. The Lebesgue coverage dimension is also associated with his name.

literature

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personal data
SURNAME Lebesgue, Henri Léon
BRIEF DESCRIPTION French mathematician
DATE OF BIRTH June 28, 1875
PLACE OF BIRTH Beauvais
DATE OF DEATH July 26, 1941
Place of death Paris