Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

Is there a way to vertically shift an underbrace downwards?

My Problem is, that the underscripts in the following code overlap:

\begin{equation*}
    \mathbf{v}_n \approx \sum_{m} \underbrace{\mathbf{T}^{(m)} \mathbf{W}}_{\mathclap{\text{m-te Transformation aller Basisvektoren}}} H_{:,n}^{(m)}.
\end{equation*}

Is there a way to solve this?

share|improve this question

3 Answers 3

If you want the explanation text all on one line, there's not much to do:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
This is what you could do
\begin{equation*}
\mathbf{v}_n \approx \sum_{\raisebox{.3ex}{$\scriptstyle m$}} 
  \underbrace{\mathbf{T}^{(m)} 
  \mathbf{W}}_{\mathclap{\substack{\text{$m$-te}\\
                                   \text{Transformation}\\
                                   \text{aller Basisvektoren}}}} 
  H_{:,n}^{(m)}.
\end{equation*}
but I'd prefer something like
\begin{equation*}
\mathbf{v}_n \approx \sum_{m} \mathbf{T}^{(m)}\mathbf{W} H_{:,n}^{(m)},
\end{equation*}
where $\mathbf{T}^{(m)}\mathbf{W}$ is the $m$-th transformation of
all basis vectors.

\end{document}

enter image description here

Alternatively,

\begin{equation*}
\mathbf{v}_n \approx \sum_{\raisebox{.3ex}{$\scriptstyle m$}}
  \underbrace{\mathbf{T}^{(m)}\mathbf{W}}%
    _{\mathclap{\substack{\uparrow\\
        \text{$m$-te Transformation aller Basisvektoren}}}}
  H_{:,n}^{(m)}.
\end{equation*}

enter image description here

I'd surely prefer the explanation after the formula.

share|improve this answer

Instead of moving the second argument of \underbrace down by some amount to keep it from clashing with the m in \sum_m, you could use \nolimits immediately after \sum to side-set the term m, thereby moving it up and out of the way of the material contained in the second argument of \underbrace.

enter image description here

Avoiding this clash solves only one typographic problem. The second argument of \underbrace is awfully long, making it less than obvious what the underbrace refers to. To alleviate this problem a bit, you could break up the underbrace material across two lines (using \substack) and set it in \tiny (rather than \scriptsize) size:

enter image description here

However, I think it's far more elegant -- and helpful to your readers! -- to place the explanation of what \mathbf{T}^{(m)} \mathbf{W} means in the body text, as @egreg suggests doing in his answer.

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{equation*}
  \mathbf{v}_n \approx \sum\nolimits_{m}   
  \underbrace{\mathbf{T}^{(m)} \mathbf{W}}_{%
  \mathclap{\text{$m$-te Transformation aller Basisvektoren}}} 
  H_{:,n}^{(m)}.
\end{equation*}
\end{document}

Code for second version of equation:

\[
  \mathbf{v}_n \approx \sum\nolimits_{m}   
  \underbrace{\mathbf{T}^{(m)} \mathbf{W}}_{%
  \mathclap{\substack{\text{\tiny $m$-te Transformation}\\ 
                      \text{\tiny aller Basisvektoren}} }}
  H_{:,n}^{(m)}.
\]
share|improve this answer

Taking @egreg's second solution as a starting point, a variant with the flalign* environment gives a better vertical spacing:

\documentclass{article}

\usepackage{mathtools}

\begin{document}

Text text text text text text text text text text text text text text text text text text text text text text text text text. 
\begin{flalign*}
 &  &  \begin{gathered}
\mathbf{v}_n \approx \sum_m\mathbf{T}^{(m)}\mathbf{W} H_{:,n}^{(m)},
 \end{gathered}  &  &  \\
\text{\rlap{where $\mathbf{T}^{(m)}\mathbf{W}$ is the $m$-th transformation of all basis vectors.}} %& &  &  &  & 
\end{flalign*}

Text text text text text text text text text text text text text text text text text text text text text text text text text.
\begin{equation*}
\mathbf{v}_n \approx \sum_m\mathbf{T}^{(m)}\mathbf{W} H_{:,n}^{(m)},
\end{equation*}
where $\mathbf{T}^{(m)}\mathbf{W}$ is the $m$-th transformation of all basis vectors.

Text text text text text text text text text text text text text text text text text text text text text text text text text.

\end{document} 

enter image description here

share|improve this answer
    
What does using the nested flalign* and gathered environments achieve in the present context? Separately, how does the use of these environments help solve the OP's issue with the clash between m (in \sum_{m} and the second argument of the subsequent \underbrace? –  Mico Jul 26 at 15:15
    
I was proposing what I think is an improvement with respect to suggesting an explanation on its own line rather than with an underbrace. –  Bernard Jul 26 at 15:22
    
Thanks. You may want to make this aspect of your contribution a wee bit more explicit. I may not be the only person who missed it... :-) –  Mico Jul 26 at 15:26
    
Yes, I know I can be somewhat elliptical at times. I'll add a few words. May I suggest the explanation (in the underbrace solution) be typed in, say, \footnotesize, so that there will be a clear difference between the formula itself and the explanation? –  Bernard Jul 26 at 15:32

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.