Émile Borel

Émile Borel
200px Émile Borel (1932)
Born	(1871-01-07)7 January 1871 Saint-Affrique, France
Died	Paris, France
Nationality	French
Fields	Mathematics, politics
Institutions	University of Paris
Alma mater	École Normale Supérieure Paris
Doctoral advisor	Gaston Darboux
Doctoral students	Robert Deltheil Paul Dienes Henri Lebesgue Paul Montel Georges Valiron
Known for	Measure theory, Probability theory

Félix Édouard Justin Émile Borel (French: [bɔʁɛl]) (7 January 1871 – 3 February 1956) was a French mathematician and politician. As a mathematician, he was known for his founding work in the areas of measure theory and probability.

Biography

Borel was born in Saint-Affrique, Aveyron, the son of a Protestant pastor. He studied at the Collège Sainte-Barbe and Lycée Louis-le-Grand before applying to both the École normale supérieure and the École Polytechnique. Although he qualified for both, he chose to attend the former institution in 1889. That year he won the concours général, an annual national mathematics competition. After graduating in 1892, he placed first in the agrégation, a competitive civil service examination leading to the position of professeur agrégé. His thesis, published in 1893, was titled Sur quelques points de la théorie des fonctions ("On some points in the theory of functions"). That year, Borel started a four-year stint as a lecturer at the University of Lille, during which time he published 22 research papers. He returned to the École normale in 1897, and was appointed to the chair of theory of function, which he held until 1941.

In 1901, Borel married 17-year-old Marguerite, the daughter of colleague Paul Émile Appel; she later wrote more than 30 novels under the pseudonym Camille Marbo. Émile Borel died in Paris on 3 February 1956.

Work

Along with René-Louis Baire and Henri Lebesgue, Émile Borel was among the pioneers of measure theory and its application to probability theory. The concept of a Borel set is named in his honor. One of his books on probability introduced the amusing thought experiment that entered popular culture under the name infinite monkey theorem or the like. He also published a series of papers (1921–27) that first defined games of strategy.

In 1913 and 1914 he bridged the gap between hyperbolic geometry and special relativity with expository work. For instance, his book Introduction Geometrique à quelques Théories Physiques described hyperbolic rotations as transformations that leave a hyperbola stable just as a circle around a rotational center is stable.

Political career

In the 1920s, 1930s, and 1940s, he was active in politics. In 1922, he founded Paris Institute of Statistics, the oldest French school for statistics. From 1924 to 1936, he was a member of the French National Assembly. In 1925, he was Minister of Marine in the cabinet of fellow mathematician Paul Painlevé. During the Second World War, he was a member of the French Resistance.

Honors

Besides the Centre Émile Borel at the Institut Henri Poincaré in Paris and a crater on the Moon, the following mathematical notions are named after him:

• Borel algebra,
• Borel's lemma,
• Borel's law of large numbers,
• Borel measure,
• Borel–Kolmogorov paradox,
• Borel–Cantelli lemma,
• Borel–Carathéodory theorem,
• Heine–Borel theorem,
• Borel summation,
• Borel distribution.

Borel also described a poker model which he coins La Relance in his 1938 book Applications de la théorie des probabilités aux Jeux de Hasard.

Borel was awarded the Resistance Medal in 1950.

Works

• On a few points about the theory of functions (PhD thesis, 1894)
• Introduction to the study of number theory and superior algebra (1895)
• Lessons on the theory of functions (1898)
• Lessons on power series (1900)
• Lessons on divergent series (1901)
• Lessons on positive terms series (1902)
• Lessons on meromorphic functions (1903)
• Lessons on growth theory at the Paris faculty of sciences (1910)
• Lessons on functions of a real variable and polynomial serial developments (1905)
• Chance (1914)
• Geometrical introduction to some physical theories (1914)
• Lessons on complex variable uniform monogenic functions (1917)
• On the method in sciences (1919)
• Space and time (1921)
• Game theory and left symetric core integral equations (1921)
• Methods and problems of the theory of functions (1922)
• Space and time (1922)
• A treaty on probability calculation and its applications (1924-1934)
• Application of probability theory to games of chance (1938)
• Principles and classical formulas for probability calculation (1925)
• Practical and philosophical values of probabilities (1939)
• Mathematical theory of contract bridge for everyone (1940)
• Game, luck and contemporary scientific theories (1941)
• Probabilities and life (1943)
• Evolution of mechanics (1943)
• Paradoxes of the infinite (1946)
• Elements of set theory (1949)
• Inaccessible numbers (1952)
• Imaginary and real in mathematics and physics (1952)
• Emile Borel complete works (1972)

Articles

• (French) "La science est-elle responsable de la crise mondiale?", Scientia : rivista internazionale di sintesi scientifica, 51, 1932, pp. 99–106.
• (French) "La science dans une société socialiste", Scientia : rivista internazionale di sintesi scientifica, 31, 1922, pp. 223–228.
• (French) "Le continu mathématique et le continu physique", Rivista di scienza, 6, 1909, pp. 21–35.

External links

• .
• Author profile in the database zbMATH