Math & Science ⇒ Cross-reference

[svend_tveskaeg]

Hi all.

Consider the following MWE:

Code: Select all

\documentclass{article}
\usepackage{mathtools}

\begin{document}
\begin{align*}
  x
  &= a\\
  &\stackrel{\mathclap{(^{\ast})}}{=} b.
\end{align*}
See $(^{\ast})$.
\end{document}

I would like to have an equation where no equation numbers are shown in the right (or left) side of the page but with a cross-reference that is shown as $(^{\ast})$ instead of me having to write it manually both in and after the equation. (I hope it makes sense...)

How do I do this?

Thank you in advance!

[kaiserkarl13]

How about this?

Code: Select all

\documentclass{article}
\usepackage{amsmath}

\begin{document}
  \begin{equation}
    \begin{split}
      x &= a \\
        &= b
    \end{split}
    \tag{$\ast$}
    \label{eq:test}
  \end{equation}
  See~\eqref{eq:test}.
\end{document}

BTW, I love your signature line.

[svend_tveskaeg]

I would like the reference to be over the equal sign.

PS. Thanks regarding the signature.