Local Fields
《Local Fields》 · 第 99 页 · Chapter VI，Section 2「Artin Representation」，Brauer's Theorem
Brauer's Theorem. Every character of a finite group is a $\mathbb Z$-linear combination of characters $\chi_i^*$ induced by characters $\chi_i$ of degree $1$ of subgroups $H_i$ of $G$.