Is a character $\chi$ realizable over $K\cap L$ where $\chi$ realize over $K$ and $L$?

31 Views Asked by At

I want to ask about realization problem of characters of a finite group. In this question, $G$, $m$, $\chi$, $K$, and $L$ are defined as follows:

.

$G$: a finite group

$m$: the exponent of $G$

$\chi$: a faithful irreducible complex character of $G$

$K$, $L$: number fields where $\chi$ is realizable

.

I wonder if $\chi$ is realizable over $K\cap L$. More precisely, you may assume that $L=\mathbb{Q}\left(\zeta_{m}\right)$ because Brauer's theorem says that $\chi$ realizes over $\mathbb{Q}\left(\zeta_{m}\right)$.

If you need, you may assume some conditions on $G$.