# using tag within align

I have the following code:

\begin{align}
[m] &= [n] \nonumber \\

&= b
\refstepcounter{equation}
\label{eq:m}
\tag{\theequation,~tag}
\end{align}


If I cross reference the equation, with Equation~\ref{eq:m}, I want only the equation number, without the word 'tag'. Can this be done? Thanks a lot.

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Use \ltx@label, which is the default \label inside a display environment. From the amsmath documentation:

... we store the default definition of \label in \ltx@label and then define a new version of \label for use in math display environments. \label@in@display merely issues a warning message if there is already a pending label (which will be discarded) and then stores the label in \df@label.

Below I've wrapped it inside a user interface \ltxlabel:

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\makeatletter
\newcommand{\ltxlabel}{\ltx@label}
\makeatother
\begin{document}
\begin{align}
[m] &= [n] \nonumber \\
&= b \refstepcounter{equation}\ltxlabel{eq:m}\tag{\theequation,~tag}
\end{align}
See Equation~\ref{eq:m}.
\end{document}


Since you're using amsmath, you may consider using \eqref.

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