Left numbered equation inside list environment

Question

I use the mathtools package with the leqno option in the memoir class. When inside a list environment, the equation label is misaligned.

\documentclass{memoir}

\usepackage[leqno]{mathtools}

\begin{document}
\begin{enumerate}
\item Inside list:
  \begin{equation}
    x=y.
  \end{equation}
\end{enumerate}

Outside list.
\begin{equation}
  x\neq y.
\end{equation}

\end{document}

Does anyone know a workaround to this? I've tried changing some list spacing lengths before the display environment but that did not work.

Answer 1

This is a "feature" of the standard classes; however the AMS classes offer a way out:

\documentclass{memoir}

\usepackage[leqno]{mathtools}

%%% ADDED CODE FROM amsbook.sty
\newcommand\fullwidthdisplay{\displayindent0pt \displaywidth\columnwidth}
\AtBeginDocument{
  \everydisplay\expandafter{\expandafter\fullwidthdisplay\the\everydisplay}
}
%%%

\begin{document}
\begin{enumerate}
\item Inside list:
  \begin{equation}
    x=y.
  \end{equation}
\end{enumerate}

Outside list.
\begin{equation}
  x\neq y.
\end{equation}

\end{document}

The equations will be centered to the line width, which is probably what you want.

However, the equation number will conflict with the item numbers; I prefer right equation numbers, in general, and particularly for these situations.