# [texhax] using align, array, eqnarry within tabular environment

Barbara Beeton bnb at ams.org
Thu Apr 9 17:25:26 CEST 2009

On Thu, 9 Apr 2009, Stephen Tucker wrote:

I have a question regarding the use of align, array, or eqnarray within a table created by tabular. Align works fine by itself, or within a minipage. For example:

===================================
\documentclass{article}
\usepackage{amsmath}
\begin{document}

\begin{align*}
x \protect & = y+1  \\
z \protect & = 2 x
\end{align*}

\end{document}
===================================

However, the following (- align nested within tabular -) gives
! LaTeX Error: \begin{document} ended by \end{tabular}.
! Missing inserted. and so on... =================================== \documentclass{article} \usepackage{amsmath} \begin{document} \begin{tabular}{cc} \begin{minipage}{2in} \flushleft text \end{minipage} & \begin{align*} x & = y+1 \\ z & = 2 x \end{align*} \end{tabular} \end{document} ================================== Even if I try to put \protect in front of & and \\, it still has problems, and putting \protect{\begin{align*}...\end{align*}} will put the statement on the next line rather than in the second column of the table, as I desire. Does anyone know how to get around this behavior? Thanks very much in advance, the align environment works only at "outer" level (which can be directly within a minipage); it cannot be used within any other environment, particularly within another display environment. instead, use the aligned environment: =================================== \documentclass{article} \usepackage{amsmath} \begin{document} \begin{tabular}{cc} \begin{minipage}{2in} \flushleft text \end{minipage} &\begin{aligned}
x & = y+1  \\
z & = 2 x
\end{aligned}\$
\end{tabular}

\end{document}
==================================

see the section on "alignment building blocks" in
the amsmath user's guide (amsldoc.pdf), p.7.

any of these subsidiary environments must be
in math mode.
-- bb