Henri Leon Lebesgue

Henri Léon Lebesgue (ɑ̃ʁi leɔ̃ ləbɛɡ; Beauvais, June 28 1875 - Paris, July 26, 1941) was a French mathematician.

Biography

She was born in Beauvais, Oise, Picardie, France. He studied at the Ecole Normale Supérieure and in the period 1899-1902 he taught at the Lycée de Nancy. In 1910 he received a professorship at the Sorbonne University.

Mathematical contributions

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

Lebesgue is mainly known for his contributions to measure and integral theory. Building on the work of other mathematicians such as Émile Borel and Camille Jordan, Lebesgue made important contributions to the theory of measurement in 1901. The following year, in his thesis Intégrale, longueur, aire ( Integral, length, area) presented at the University of Nancy, defined the Lebesgue integral, which generalizes the notion of the Riemann integral by extending the concept of area under a curve to include discontinuous functions. This is one of the achievements of modern analysis that expands the scope of Fourier analysis.

He also contributed to branches such as topology, potential theory and Fourier analysis. In 1905 he presented a discussion of the conditions that Lipschitz and Jordan had used to ensure that f(x) is the sum of their Fourier series.

From 1910 he no longer concentrated on the area of study that he had started, because his work was a generalization, and he was fearful of it. In his words: Reduced to general theories, mathematics would be a beautiful form without content. They would die quickly. Although later developments showed that his fear was unfounded, it allows us to understand the course his work followed.

Works

In addition to approximately 50 articles, he wrote two books: Leçons sur l'intégration et la recherché des fonctions primitives (1904) and Leçons sur les séries trigonométriques (1906).

Eponymy

In addition to the different mathematical concepts that bear his name, one must:

• The lunar crater Lebesgue bears this name in his memory.
• The asteroid (26908) Lebesgue also commemorates its name.