The & causes trouble in an array using package versions

Asked Feb 13 '24 at 16:48

Active Feb 13 '24 at 16:48

Viewed 45 times

I have this MWE

\documentclass{book}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{versions}
%\excludeversion{teacher}
\includeversion{teacher}
\begin{document}
\begin{eqnarray}
  a+b&=&c\
  \begin{teacher}X = \end{teacher}\
c+d&=&e\
\end{eqnarray}
\end{document}

This works fine, but I like to align = nicely. As soon as I use \begin{teacher}X &=& \end{teacher}\\ I get the error:

! Extra }, or forgotten \endgroup. } $@eqnsel \endtemplate l.13 \begin{teacher}X & =& \end{teacher}\

asked Feb 13 '24 at 16:48

lukascbossert

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3

you can't start an environment in one alignment cell and close it in another/ – David Carlisle Feb 13 '24 at 16:50
1

Try with \begin{teacher}X\end{teacher} &\begin{teacher}=\end{teacher}&\\ – samcarter_is_at_topanswers.xyz Feb 13 '24 at 16:51
2

Do not overstretch the comment/uncomment stuff. Bite the bullet and repeat the whole equation if you want a teacher and no-teacher version. – Ulrike Fischer Feb 13 '24 at 16:54
1

@samcarter_is_at_topanswers.xyz That did the trick. – lukascbossert Feb 13 '24 at 16:59
Never use eqnarray. – egreg Feb 13 '24 at 21:58

The & causes trouble in an array using package versions

0 Answers0