$$
\begin{align}
a = b
\label{my equation}
\end{align}
$$
Equation \ref{my equation} is my equation.
I plan on editing my question Alternative representation of the covariant derivative? to make it more compact and concise, but it would be nice to save time and not have to renumber all of the equations manually a third time.
\tag{}
(MathJax doesn't process it). Curiously, however, using$\ref{ref1}$
in the body does produce a (dead) hyperlink. $\endgroup$