Johann Peter Gustav Lejeune Dirichlet

Johann Peter Gustav Lejeune Dirichlet (February 13, 1805 - May 5, 1859) was a German mathematician credited with the modern "formal" definition of a function.

Related Topics:
February 13 - 1805 - May 5 - 1859 - German - Mathematician - Function

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

His family hailed from the town of Richelet in Belgium, from which his surname "Lejeune Dirichlet" ("le jeune de Richelet" = "the young chap from Richelet") was derived, and that was where his grandfather lived.

Related Topics:
Richelet - Belgium

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Dirichlet was born in Düren, where his father was the postmaster. He was educated in Germany, and then France, where he learnt from many of the most renowned mathematicians of the day. His first paper was on Fermat's last theorem. This was a famous conjecture (now proven) that stated that for n > 2, the equation xn + yn = zn has no integer solutions, apart from the trivial ones in which x, y, or z is zero. He produced a partial proof for the case n = 5, which was completed by Adrien-Marie Legendre, who was one of the referees. Dirichlet also completed his own proof almost at the same time; he later also produced a full proof for the case n = 14.

Related Topics:
Düren - Postmaster - Germany - France - Fermat's last theorem - Adrien-Marie Legendre

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

He married Rebecca Mendelssohn, who came from a distinguished Jewish family, being a granddaughter of the philosopher Moses Mendelssohn, and a sister of the composer Felix Mendelssohn.

Related Topics:
Rebecca Mendelssohn - Jew - Moses Mendelssohn - Felix Mendelssohn

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Ferdinand Eisenstein, Leopold Kronecker, and Rudolf Lipschitz were his students. After his death, Dirichlet's lectures and other results in number theory were collected, edited and published by his friend and fellow mathematician Richard Dedekind under the title Vorlesungen über Zahlentheorie (Lectures on Number Theory).

Related Topics:
Ferdinand Eisenstein - Leopold Kronecker - Rudolf Lipschitz - Number theory - Richard Dedekind - Vorlesungen über Zahlentheorie

~ ~ ~ ~ ~ ~ ~ ~ ~ ~