Math & Science ⇒ Vertical Alignment of Text When Using Multiple Underbraces

[cbkschroeder]

Hi!

Thanks for taking the time to read my posting.

I have the following equation:

Code: Select all

\frac{1}{T_{2}^\ast}=\underbrace{\frac{1}{T_2}}_\text{Irreversible}+\underbrace{\frac{\gamma}{2\pi}\Delta B}_\text{Reversible}

The two terms on the right of the equal sign are both "underbraced". When one compiles this document, however, the result is that there is no vertical alignment of the text which accompanies the underbraces. In other words, the final product has "Irreversible" sit slightly (but very noticeably) lower on the page than "Reversible". Is there any way to ensure consistent vertical alignment of text in multiple-underbrace scenarios? Perhaps an even better solution would be to have text sit at a constant distance below each underbrace but instead have the underbraces vertically aligned...

Your (always helpful) thoughts would be much appreciated; thanks for your time!

Christian

[Stefan Kottwitz]

Hi Christian,

a quick workaround would be to use \vphantom to ensure the vertical alignment:

Code: Select all

\frac{1}{T_{2}^\ast}=\underbrace{\frac{1}{T_2}}_\text{Irreversible}
+\underbrace{\frac{\gamma}{2\pi\vphantom{T_2}}\Delta B}_\text{Reversible}

Stefan

[localghost]

Another approach could be to make the compiler neglect the vertical size of the denominator in the first fraction on the right side of the equation.

Code: Select all

\begin{equation}
  \frac{1}{T_{2}^\ast}=\underbrace{\frac{1}{\smash{T_2}}}_\text{Irreversible}+\underbrace{\frac{\gamma}{2\pi}\,\Delta B}_\text{Reversible}
\end{equation}

Best regards
Thorsten¹

[cbkschroeder]

Thank you both for your quick replies. Of the two contrasting solutions, using the \vphantom creates a subtly more pretty equation. Using \smash seems to crowd things a bit.

Thorsten, thanks for your subtle insertion of a "\,"; it does make things prettier!

Again, thank you both!

Christian

[adnaniut]

Hi guys,

I have a similar problem of vertical alignment in array. Could you please suggest me how can I align n and m in same level.

Thanks
Adnan

Code: Select all

$$ =\left[
 \underbrace{
\begin{array}{ccccc}
 \displaystyle\frac{\displaystyle \sum_{i=0}^{n-1} q_2^i + q_2^n}{q_2^n} &
 \displaystyle \frac{\displaystyle \sum_{i=0}^{n-2} q_2^i + q_2^n}{q_2^n} &
  \cdots &
  \displaystyle \frac{\displaystyle \sum_{i=0}^{n-(n+1)} q_2^i + q_2^n}{q_2^n} &
   \displaystyle \frac{1 + q_2^n}{q_2^n} 
    \end{array}
  }_n
\underbrace{%
    \begin{array}{ccc}
   1 &
    \cdots &
    1 
        \end{array}
    }_m
    \right]^T$$

[gmedina]

Hi,

you could use a "vertical phantom":

Code: Select all

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\[
  =\left[
  \underbrace{
  \begin{array}{ccccc}
    \dfrac{\sum\displaystyle_{i=0}^{n-1} q_2^i + q_2^n}{q_2^n} &
    \dfrac{\displaystyle \sum_{i=0}^{n-2} q_2^i + q_2^n}{q_2^n} &
    \cdots &
    \dfrac{\displaystyle \sum_{i=0}^{n-(n+1)} q_2^i + q_2^n}{q_2^n} &
    \dfrac{1 + q_2^n}{q_2^n} 
  \end{array}
  }_n
  \underbrace{%
  \begin{array}{ccc} &\\[-10pt]
    1 & \cdots & 
    1\vphantom{\dfrac{\displaystyle\sum_{i=0}^{n-1} q_2^i + q_2^n}{q_2^n}}
  \end{array}
  }_m
  \right]^T
\]

\end{document}

Note that I used \[...\] instead of the obsolete $$...$$ construct.