Dirichlet, Peter Gustav Lejeune

Dirichlet, Peter Gustav Lejeune 

Born Feb. 13, 1805, in Düren; died May 5, 1859, in Göttingen. German mathematician. Dirichlet was a professor at the University of Berlin from 1831 to 1855 and at the University of Göttingen from 1855. His principal works were in the theory of numbers and mathematical analysis. Dirichlet proved the theorem of the existence of an infinitely large number of prime numbers in any arithmetic progression of whole numbers, the first member and difference of which are relatively prime numbers. In the field of mathematical analysis Dirichlet was the first to precisely formulate and study the concept of the conditional convergence of a series, and he provided a rigorous proof of the possibility of the expansion in a Fourier series of a function having a finite number of maxima and minima. Significant works by Dirichlet are devoted to mechanics and mathematical physics.

WORKS

Vorlesungen über die im umgekehrten Verhältniss des Quadrats der Entfernung wirkenden Kräfte, 2nd ed. Leipzig, 1887.
Die Darstellung ganz willkürlicher Functionen durch Sinus- und Cosinusreihen. Leipzig, 1900. (Ostwald’s Klassiker der exakten Wissenschaften, no. 116.)

REFERENCE

Klein, F. Lektsii o razvitii matematiki v 19 stoletii, part 1. Moscow-Leningrad, 1937. (Translated from German.)