Henri Lebesgue

Henri Léon Lebesgue [ ɑʁi ː leɔ ləbɛg ] ( born June 28, 1875 in Beauvais, † July 26, 1941 in Paris) was a French mathematician.

He expanded the integral term, arguing that measure theory. Named after him are the Lebesgue measure and the Lebesgue integral. The Lebesgue measure generalized dimensions previously used (such as the Jordan - degree ) and was as well as the corresponding Lebesgue integral soon became the standard tool in the real analysis.

Life

He lost his father, a translator, by early tuberculosis and was able to visit high schools, where he received top marks only thanks to the support of his hard-working mother. He studied from 1894 to 1897 at the École normale supérieure and taught from 1899 to 1902 as a high school teacher in Nancy. There, he also succeeded in the discovery of named after him integral ( Sur une generalization de l' intégrale define, Comptes Rendus 1901). After about even 1902 ( Intégrale, Longueur, Aire, Annali di Mathematica) received his doctorate, he received his first university post in Rennes. In 1906 he became professor of mechanics in Poitiers. In recognition of his achievements but he kept while already courses at the College 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 was awarded an assistantship at the Sorbonne, where he became professor in 1918. From 1921 he was professor at the College de France.

He was married from 1903 to 1916 and had two children. The lunar crater Lebesgue is named after him.

Services

The importance of Lebesgue's ideas is that his theory of integration ( of the Lebesgue integral ) has a number of useful properties that the Riemann integral was missing (about completeness ). Many basic phrases in this area come from him, such as the set of Lebesgue. In addition to his theory of integration, he also served on Fourier series, potential theory and other problems of analysis. In addition, he worked on geometry and the history of mathematics. The Lebesgue'sche coverage dimension is associated with his name.