A Classical Introduction to Modern Number Theory
《A Classical Introduction to Modern Number Theory》 · 第 309 页 · Section 18.5「Hecke L-functions」
We now proceed to attach an L-function to an algebraic Hecke character $\chi$. Namely, define $L(s,\chi)=\prod_{\mathfrak p}(1-\chi(\mathfrak p)N\mathfrak p^{-s})^{-1}$; the product is over all prime ideals in $\mathcal O$.