1805-1859

German Mathematician

Lejeune Dirichlet was a professor at the University of Berlin prior to accepting a chair—previously held by Carl Gauss (1777-1855)—at the University of Göttingen. Perhaps Dirichlet's most valuable contribution to science was in the theory of the Fourier series, which he originated. He also made important contributions to algebraic number theory and harmonic functions.

Dirichlet was born in Düren, then part of the French Empire and now part of Germany. The first mention of his work appears in 1826, when he proved one of Gauss's conjectures about prime numbers. The next year he was awarded a teaching position at the University of Breslau, after which he moved to the University of Berlin in 1828 and, in 1855, to Göttingen.

It was during his time at Berlin that Dirichlet first proposed what is the currently accepted...