# Align text using align* environment

I would like to align text using the align* environment.

What I would like to do in the example below is to align the different elements inside the braces after # meaning. So, I would like to have indefinite(?x), masculine(?x) and singular(?x) below each other and aligned.

I have tried inserting another align* environment, but this gives me the error: Argument of \align* has an extra }

How can I do this? If this can be done in another way, i.e. not using the align* environment, this is fine for me either.

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

\begin{footnotesize}
\begin{align*}
&\left[
\begin{tabular}{l}
\textbf{?un-word}\\
\hline \hline
args: \lbrack ?x \rbrack\\
syn-cat: \\
\end{tabular}
\right]
\leftarrow
&\left[
\begin{tabular}{l}
\textbf{?un-word}\\
\hline \hline
\# meaning: \{indefinite(?x), masculine(?x), singular(?x)\}\\
\hline
\# form: \{string(?un-word, un)\}\\
\end{tabular}
\right]
\tag{un-cxn}
\end{align*}
\end{footnotesize}
\end{document}


I think it's not possible to use align environments inside tabular, but you can use tabular inside other tabulars. In this case you can align all elements after meaning with a new tabular with option [t] to align its top line with previous text. The final brace } is included after last element, because I don't know how to align with bottom tabular line.

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

\begin{footnotesize}
\begin{align*}
&\left[
\begin{tabular}{l}
\textbf{?un-word}\\
\hline \hline
args: \lbrack ?x \rbrack\\
syn-cat: \\
\end{tabular}
\right]
\leftarrow
&\left[
\begin{tabular}{l}
\textbf{?un-word}\\
\hline \hline
\# meaning: \{\begin{tabular}[t]{@{}l@{}}
indefinite(?x),\\
masculine(?x),\\
singular(?x)\}
\end{tabular}\\
\hline
\# form: \{string(?un-word, un)\}\\
\end{tabular}
\right]
\tag{un-cxn}
\end{align*}
\end{footnotesize}
\end{document}


• This is not what I mean in my question. I would like indefinite(?x), masculine(?x) and singular(?x) to be below each other and aligned. The three elements inside the curly braces, after # meaning in the right part. – JNevens Dec 28 '15 at 16:06
• @JNevens Sorry, I've misunderstood the question. I've updated my answer, is it better now? – Ignasi Dec 28 '15 at 17:08
• I would get rid of the align and use equation without the &s. – Werner Dec 28 '15 at 17:46
• @Ignasi This is what I was looking for, thank you! @Werner In this example, the outer align* environment is indeed useless, but I have some bigger constructions like this where alignment is done on left[ – JNevens Dec 28 '15 at 18:06