# overbrace but leave spacing in math unaffected

I would like to use an overbrace, but I do not want how much text I put in the overbrace to affect the spacing of the math (i.e. I don't want the the "a" and the "b" to get further apart in the following example):

$\frac{a-\overbrace{b^d}^{\text{'d' here stands for 'dummy variable', it is not an exponent}}}{c}$


Any ideas? This particular example is pretty silly and I would not do it in practice, but it is just to make things simple.

Depending on the situation, maybe you can use \mathclap from mathtools.

For example,

\documentclass{article}
\usepackage{amsmath}
\usepackage{mathtools}
\begin{document}
$\frac{a-\overbrace{b^d}^{\mathclap{\text{'d' here stands for 'dummy variable', it is not an exponent}}}}{c}$
\end{document}

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\frac{a-\overbrace{b^d}^{ \hidewidth \text{'d' here stands for 'dummy variable', it is not an exponent} \hidewidth }}{c}$
\end{document}


So, the \hidewidth, well, hides the width.

• \text is defined in amstext whis would be automatically loaded by amsmath. It cannot be seen in the question, but the the tag {amsmath} has been used. – Stefan Kottwitz Feb 20 '11 at 18:07