[texhax] Re-using equation numbers

[CV Radhakrishnan]

<quote who="Robin Fairbairns">
>> The following is a numbered equation in an early chapter of a
>> thesis
>> \begin{equation}
>> \mathrm{\dot{H} + O_2  \rightarrow  \dot{O}H + O }
>> \label{key}
>> \end{equation}
>>
>> We want to re-use the equation number in a restatement of the
>> equation  many pages on from the first statement because the
>> reader
>> may well have forgotten what it referred to ...
>>
>> Is there a better or more elegant solution than this?
>>
>> $$
>> \mathrm{\dot{H} + O_2 \rightarrow \dot{O}H + O }  \rule{25pt}{0pt}
>> \eqref{key}
>> $$
>>
>> in LaTeX + Amsmath
>
> don't use $$ in amsmath; use the amsmath \tag command:
>
> \[ \mathrm{\dot{H} + O_2 \rightarrow \dot{O}H + O }
> \tag{\eqref{key}} \]

Without AMS Math, \eqno command can replace \tag, meaning
\eqno{(\ref{key})} can accomplish the same results as above.

-- 
Radhakrishnan