Frobenius reciprocity
= Frobenius reciprocity
{c}
{wiki}
For $H\leq G$, an $H$-representation $V$, and a $G$-representation $W$,
$$
\operatorname{Hom}_G(\operatorname{Ind}_H^GV,W)
\cong
\operatorname{Hom}_H(V,\operatorname{Res}_H^GW).
$$
Equivalently, induction and restriction are adjoint for character inner products.