Math & Science ⇒ braces under matrix entry affect matrix braces

[Wayne_Durden]

Hi,

I got a "problem" (if you can call it one) with brackets under entries in a matrix:
They affect the brackets of the matrix, so the whole thing looks kind of weird, because the bracket "get's part of the matrix entry" and causes a higher bracket.
Is it possible to arrange the brackets "under" the matrix, not affecting the entry/column they are referring?

I hope I could explain my problem.

Greetings

[frabjous]

I hope I could explain my problem.

Greetings

Code containing a minimal example of what you mean would be better.

[Wayne_Durden]

Oh, I am sorry I didn't mention that!

Here's the code:

Code: Select all

\begin{equation} \left[\begin{array}{c} \begin{array}{c} \dot{s}
\end{array}\\ \dot{v}\end{array}\right]=\left[\begin{array}{cc} 
0 & 1\\ 0 & \underbrace{-\frac{d_{m}}{m_{red}}}_{Reibverl.}
\underbrace{-\frac{i_{\textrm{A}}^{2}k_{m}^{2}}
{r^{2}m_{red}R_{\textrm{A}}}}_{elektr.\, Verl.}\end{array}
\right]\cdot\left[\begin{array}{c} s\\ v\end{array}\right]+
\left[\begin{array}{c} 0\\ 
\underbrace{\frac{i_{\textrm{A}}k_{m}}
{rR_{\textrm{A}}}}_{\text{ß}}\cdot\frac{1}{m_{red}}\end{array}
\right]u_{\textrm{A}}\end{equation}

(The code is exported from a LyX-file btw)
I hope this helps!
Thanks a log!

[frabjous]

Here I define a \myunderbrace command which ignores the underbrace part for height calculations. Notice that its syntax is \myunderbrace{..}{...} rather than \myunderbrace{..}_{..} as with standard \underbrace. I'd explain the details but it might be better for you to work them out on your own, and/or tweak it if need be.

Code: Select all

\documentclass{article}

\newlength{\bracewidth}

\newcommand{\myunderbrace}[2]{\settowidth{\bracewidth}{$#1$}#1\hspace*{-1\bracewidth}\smash{\underbrace{\makebox{\phantom{$#1$}}}_{#2}}}

\usepackage{amsmath}

\begin{document} 
\begin{equation} \left[\begin{array}{c} \begin{array}{c} \dot{s}
\end{array}\\ \dot{v}\end{array}\right]=\left[\begin{array}{cc}
0 & 1\\ 0 & \myunderbrace{-\frac{d_{m}}{m_{\textit{red}}}}{\textit{Reibverl.}}
\myunderbrace{-\frac{i_{\textrm{A}}^{2}k_{m}^{2}}
{r^{2}m_{\textit{red}}R_{\textrm{A}}}}{\textit{elektr.\ Verl.}}\end{array}
\right]\cdot\left[\begin{array}{c} s\\ v\end{array}\right]+
\left[\begin{array}{c} 0\\
\myunderbrace{\frac{i_{\textrm{A}}k_{m}}
{rR_{\textrm{A}}}}{\text{\ss}}\cdot\frac{1}{m_{\textit{red}}}\end{array}
\right]u_{\textrm{A}}\end{equation}

\end{document}

This generates:

brace.png (5.48 KiB) Viewed 8751 times

Is that what you had in mind?

[Wayne_Durden]

Thank you a lot! That was exactly I was looking for!
You made my day!

[localghost]

Now that the problem is solved, please be so kind and mark the topic (not the last post) accordingly as clearly written in Section 3 of the Board Rules (to be read before posting). Please keep that in mind for the future so that further reminders will not be necessary.


Best regards and welcome to the board
Thorsten