埃米尔·皮卡1856—1941

生平

皮卡出生于巴黎。1877年毕业于巴黎高等师范学校，获博士学位。1879年，在图卢兹大学任教，此后曾在巴黎高等师范学校、巴黎大学任职。1924年成为法兰西学院院士。

成就

皮卡的主要贡献在于解析函数、微分方程以及代数几何学等方面。1879年，他提出皮卡小定理，次年证明皮卡大定理。这两个定理为复变函数论指引了新的方向。1883年–1888年，皮卡将庞加莱自守函数的方法推广到二元复变函数，进而研究代数曲面，建立“皮卡群”（Picard Group）。他还推广了逐步逼近法。

Charles Émile Picard (French: [ʃaʁl emil pikaʁ]; 24 July 1856 – 11 December 1941) was a French mathematician. He was elected the fifteenth member to occupy seat 1 of the Académie française in 1924.

Life

He was born in Paris on 24 July 1856 and educated there at the Lycée Henri-IV. He then studied mathematics at the École Normale Supérieure.

Picard's mathematical papers, textbooks, and many popular writings exhibit an extraordinary range of interests, as well as an impressive mastery of the mathematics of his time. Picard's little theorem states that every nonconstant entire function takes every value in the complex plane, with perhaps one exception. Picard's great theorem states that an analytic function with an essential singularity takes every value infinitely often, with perhaps one exception, in any neighborhood of the singularity. He made important contributions in the theory of differential equations, including work on Picard–Vessiot theory, Painlevé transcendents and his introduction of a kind of symmetry group for a linear differential equation. He also introduced the Picard group in the theory of algebraic surfaces, which describes the classes of algebraic curves on the surface modulo linear equivalence. In connection with his work on function theory, he was one of the first mathematicians to use the emerging ideas of algebraic topology. In addition to his theoretical work, Picard made contributions to applied mathematics, including the theories of telegraphy and elasticity. His collected papers run to four volumes.

Louis Couturat studied integral calculus with Picard in 1891–1892, taking detailed notes of the lectures. These notes were preserved and now are available in three cahiers from Internet Archive.

Like his contemporary, Henri Poincaré, Picard was much concerned with the training of mathematics, physics, and engineering students.

He wrote a classic textbook on analysis and one of the first textbooks on the theory of relativity. Picard's popular writings include biographies of many leading French mathematicians, including his father in law, Charles Hermite.

Picard was an International Honorary Member of the American Academy of Arts and Sciences, an International Member of the United States National Academy of Sciences, and an International Member of the American Philosophical Society.

Family

In 1881 he married Marie, the daughter of Charles Hermite.

Society

Charles Émile Picard was one of the founder members in 1930 of the Society of Friends of André-Marie Ampère which was created to develop the first science museum in France, the Ampère Museum close to Lyon.