# Apostrophe in math formula prevents luatex compilation for Slovak

The following example can be compiled with pdflatex or xelatex without any problems, but with lualatex, the compilation comes never to an end.

\documentclass{article}
\usepackage[slovak]{babel}
\begin{document}
$f'$
\end{document}


What is wrong here?

## 1 Answer

slovak.ldf loaded by \usepackage[slovak]{babel} is from 2008, it has not be adapted to the unicode engines and is imho completly useless and unsuited.

An alternative is to use the new ini-files from babel:

\documentclass{article}
\usepackage{babel}
\babelprovide[import=sk, main]{slovak}
\begin{document}
\tableofcontents
\section{aaa}
$f'$
\end{document}


• With this solution, active characters are not available. It is clear that the problem cannot occur without active characters, but I need them. – wehro Sep 14 at 13:37
• which active character do you need for what? – Ulrike Fischer Sep 14 at 13:43
• I need 'a for á. – wehro Sep 14 at 14:47
• Why? can't you simply type á? – Ulrike Fischer Sep 14 at 14:53
• It's for backwards compatibility. – wehro Sep 15 at 17:29