Dirichlet eta function

English

Etymology

Named after Johann Peter Gustav Lejeune Dirichlet (1805–1859), German mathematician.

Proper noun

1. Template:Lb The alternating sum of the Dirichlet series expansion of the Riemann zeta function: Template:C$\eta (s)=\sum _{n=1}^{\mathrm{\infty }}\frac{(-1{)}^{n-1}}{n^s}=\frac{1}{1^s}-\frac{1}{2^s}+\frac{1}{3^s}-\frac{1}{4^s}+\cdots .$