# Motivation

When I use math mode inside of itemize environments for multiline equations, I have to do something like the following

...
\begin{itemize}
\item \begin{aligned}[t] equation stuff \end{aligned}
...
\end{itemize}
...


# Question

How can I wrap the two components \begin{aligned}[t] and \end{aligned} into a new symbol, e.g. §? I'd like to write the above example as

...
\begin{itemize}
\item §equation stuff§
...
\end{itemize}
...


It is favorable for the solution to be robust.

(It is not required for the new symbol to be §.)

• How about a macro \mleq defined as \newcommand\mleq[1]{\begin{aligned}[t] #1 \end{aligned}? – Herr K. Aug 21 '13 at 15:19
• – Qrrbrbirlbel Aug 21 '13 at 19:32
• @Qrrbrbirlbel Is it then not recommended to use aligned? What do you propose instead? – Henri Menke Aug 23 '13 at 13:51
• @HenriMenke No. I don’t know of a better alternative (except maybe an array solution). As you can see in the numerous linked references you will just to insert a \!. – Qrrbrbirlbel Aug 24 '13 at 5:14

The \catcode§=\active method won't work if the document declares

\usepackage[utf8]{inputenc}


because § is a two byte character in UTF-8. For this case you can use

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}

\usepackage{newunicodechar}
\newunicodechar{§}{\mymath}
\def\mymath#1§{\begin{aligned}[t] #1\end{aligned}}

\newenvironment{itemalign}
{\aligned[t]} {\endaligned}

\begin{document}
\begin{itemize}
\item §x&=2\\y&=6§
\item \begin{itemalign}x&=2\\y&=6\end{itemalign}
\end{itemize}
\end{document}


that has the advantage of working also with LuaLaTeX and XeLaTeX (where the call to inputenc should not be present).

However, I'd recommend using the new environment method.

• You used \aligned to open the envorinment, but you used \endalignedat to close it (Note the trailing at). Anyway it works, but why? And why don't you use \endaligned? – Henri Menke Aug 23 '13 at 19:26
• @HenriMenke Thanks for noting! I checked and discovered that \endalignedat executes \endalign. ;-) But it's wrong anyway. – egreg Aug 23 '13 at 19:40
• I used the \newenvironment solution. To make it more align-like I'd like to add a new line at the end of itemalign. I used {\endaligned\par}, but I doubt, that this is the right procedure, because this will start a new paragaph after each itemalign. What do I have to insert instead of \par? – Henri Menke Aug 28 '13 at 20:56 • @HenriMenke I believe this should be the entire item, so you need nothing after it. – egreg Aug 28 '13 at 21:04 If I were you, I would use two different macros to open and close the environment. I would do something like \def\ba#1\ea{\begin{aligned}[t]#1\end{aligned}$}  that can be use like that \begin{itemize} \item \ba equation stuff \ea \end{itemize}  How about making § active? \documentclass{article} \usepackage{amsmath} \catcode§=\active \def§#1§{$\begin{aligned}[t] #1\end{aligned}\$}

\begin{document}
\begin{itemize}
\item §x&=2\\y&=6§
\end{itemize}
\end{document}


Then we can scan an argument up to the next occurence of § and wrap this in aligned.

As @egreg pointed out, this will be problematic using pdflatex and inputenc (see also: Catcodes of unicode characters with \usepackage[utf8]{inputenc}). A simple workaround in this case is changing § to e.g. |.

• This would not work with \usepackage[utf8]{inputenc} – egreg Aug 21 '13 at 15:44
• @egreg fair point! It works with my xelatex, however, so I didn't notice. Changing the character from § to e.g. | fixes that though. – Jonathan Aug 21 '13 at 16:22