Why aren't the $K$
and $\chi$
vertically aligned in the following example and is there a simple workaround?
\documentclass[a4paper,11pt,twoside=semi]{scrbook}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\begin{document}
$\mathcal{D}_{K,\chi}$
\end{document}
The output is