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I am currently writing my master thesis, and I have just noticed that I have a problem, that I don't know how to solve. My thesis is divided into several chapters. In the first chapter I have an equation, which I want to state again in the second chapter, with the same equation number. To do this I use \tag, by writing \tag{\ref{eq:1}}. The problem is that after doing this, the equation counter resets. So now I have two different equations labeled (2.1).

I have been trying to cook up a minimal working example, but I can't really spot the error. So I have made an example to show what I am doing, but when I compile it, it looks as it should.

\documentclass[12pt]{memoir}
\usepackage[english]{babel}
\usepackage[ansinew]{inputenc}
\usepackage{mathtools}
\mathtoolsset{showonlyrefs,showmanualtags}

\begin{document}
\chapter{First}
First equation
\begin{equation}
\label{eq:1}
abc
\end{equation}

\chapter{Second}
Second equation
\begin{equation}
\label{eq:2}
xyz
\end{equation}
\eqref{eq:2}

Lets recap \eqref{eq:1}
\begin{equation}
\label{eq:3}
abc \tag{\ref{eq:1}}
\end{equation}
Ref: \eqref{eq:3}

And another equation
\begin{equation}
\label{eq:4}
ijk
\end{equation}
Ref: \eqref{eq:4}

\end{document}

Does anyone have an idea what the problem is - or even more importantly, how I solve it?

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closed as unclear what you're asking by Joseph Wright Aug 21 '13 at 8:39

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Welcome to TeX.SX! –  Papiro Jun 28 '13 at 15:39
2  
I have found a solution myself. The solution was to add the line \refstepcounter{equation}% between the tagged equation, and the equation with the wrong label. However, I think that this might only work, since the label it should have is (2.2), instead of (2.1) as it has been reset to. If anyone comes up with a better solution, please post it here! Someone (e.g. me) might learn something. By the way, I don't have enough reputation to post an answer to my own question yet. –  cimrg.joe Jun 28 '13 at 19:36
    
Your MWE do not produce the problem you mention when I compile it. –  Ipsen Jun 29 '13 at 16:28
    
I know. I don't know what causes the error in my large document. I tried coming up with a MWE, but as you see it didn't go too well, although it shows what I'm trying to do. –  cimrg.joe Jun 29 '13 at 17:38
    
With a MWE that doesn't actually show the issue, we are unlikely to solve this. –  Joseph Wright Aug 21 '13 at 8:39

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