# [Tex/LaTex] Using there exists symbol within inference of the semantic package

semanticssymbols

I am using the semantic package to write inference rules. I need to put a there exists symbol which is standard to LaTeX using $\exists$. However, when used within the semantic package's inference command as follows:

\inference[case$_0$]{$\exists$ I}{test}


several errors are encountered :

(./semantics.aux) (/usr/share/texmf-texlive/tex/latex/ucs/ucsencs.def)
! Missing $inserted. &lt;inserted text&gt;$
l.42 \inference[case$_0$]{$\exists$ I}
{test}
! Extra }, or forgotten $. \@processPremiseLine ...ce \end \hskip \@@pSpace } \fi \fi \def \sem@tmp {#2}... l.42 \inference[case$_0$]{$\exists$I} {test} ! Missing$ inserted.
&lt;inserted text&gt;
$l.42 \inference[case$_0$]{$\exists$I} {test} ! Missing } inserted. &lt;inserted text&gt; } l.42 \inference[case$_0$]{$\exists$I} {test} [1] (./semantics.aux) )  Can anyone suggest what I can do please? #### Best Answer You can "box" the item using \ensuremath: \documentclass{article} \usepackage{semantic}% http://ctan.org/pkg/semantic \begin{document} \inference[case$_0\$]{\ensuremath{\exists~I}}{test}
\end{document}


Note the forced spacing as a result of the tie ~. This may just be your preference, which I've stuck to.