Box aligned equation under (deep) itemization

Question

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{empheq}
\newcommand*\widefbox[1]{\fbox{\hspace{2em}#1\hspace{2em}}}

\begin{itemize}
\item[1.] zz
\begin{itemize}
\item[1.1]

\begin{subequations}
\begin{empheq}[box=\widefbox]{align}
x \;&=\; x_1 = x_2 = x_3 = x_4 = x_5 = x_6 = 0 \\
y \;&=\; y_1 = y_2 = y_3 = y_4 = y_5 = y_6 = 0 
\end{empheq}
\end{subequations}

\item[1.2]
\end{itemize}
\item[2.]
\end{itemize}
\end{document}

The box will be mis-sized, not boxing the entire equations body.

I just copied from: http://tex.stackexchange.com/questions/109900/how-can-i-box-multiple-aligned-equations — DarknessGuideMe, Apr 24 '15 at 06:11
Equation seems to be well-boxed. Please specify your actual problem. — Ambika Vanchinathan, Apr 24 '15 at 06:16
If you compile it, you will see the box is off. Does this site compile a doc? — DarknessGuideMe, Apr 24 '15 at 08:04
Your code didn't compile which made it slightly useless. I have added the missing commands, but to me the placement of the box looks fine so you need to explain what you mean by the box being off. Btw, your use of \; is unnecessary. — , Apr 24 '15 at 08:54

Bernard · Answer 1 · 2015-04-24T13:56:44.017

The equations are centred with respect to the left margin of the current itemize environment and the right margin of the page, not taking into account the equation number. A work around could be adding \hphantom{tag} to the right of the empheq environment. I also managed to get the item number vertically aligned with the first line of the align environment:

\documentclass[a4paper]{article}
\usepackage{empheq}
\usepackage{amssymb}
\newcommand*\widefbox[1]{\fbox{\hspace{2em}#1\hspace{2em}}}

\begin{document}

\begin{itemize}
  \item[1.] zz
        \begin{itemize}%[leftmargin = *]
          \item[1.1]
                \leavevmode\vspace{\dimexpr-\baselineskip-\abovedisplayshortskip}
                \begin{subequations}
                  \begin{empheq}[box=\widefbox, right = \hphantom{2a}]{align}
                    x \;&=\; x_1 = x_2 = x_3 = x_4 = x_5 = x_6 = 0 \\
                    y \;&=\; y_1 = y_2 = y_3 = y_4 = y_5 = y_6 = 0
                  \end{empheq}
                \end{subequations}
                \noindent Text text text text text text text text text text text text text text text text text text text text text text text text text
          \item[1.2]
        \end{itemize}
  \item[2.]
\end{itemize}

\end{document}

enter image description here

doesn't compile -- you're missing a closing brace at the end of the definition of \widefbox. also, amssymb is needed either; you probably meant amsmath, but with empheq that's taken care of. — barbara beeton, Apr 24 '15 at 13:51
Oh yes! Bad copy-paste… Corrected now. Thanks for pointing it :o) — Bernard, Apr 24 '15 at 13:58
Thanks a lot! just curious, do you generate the image using the site? or do you have to take screen-shot and upload? — DarknessGuideMe, Apr 24 '15 at 23:09

Box aligned equation under (deep) itemization

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