4

So I have this formula

\begin{empheq}[right=\empheqrbrace]{align*}
\dfrac{\dfrac{\dfrac{\dfrac{
    \frac{1}{a} % <-- start with this a
}{a}}{a}}{\vdots}}{a}

that's rendered in this formula:

enter image description here

which is nice, but would it be possible to start the brace just a little lower, i.e. begin with the first a; currently it begins on top, i.e. at the number 1?

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3 Answers 3

Reset to default
5

Use a double array; empheq is not the right tool.

\documentclass{article}

\usepackage{amsmath,lipsum}

\begin{document}
\lipsum*[2]
\begin{equation*}
\begin{array}{c}
\\[-.3\normalbaselineskip]
\left.
\begin{array}{@{}c@{}}
\\[-1.7\normalbaselineskip]
\dfrac{\dfrac{\dfrac{\dfrac{
    \frac{1}{a} % <-- start with this a
}{a}}{a}}{\vdots}}{a}
\end{array}
\right\rbrace
\end{array}
\end{equation*}
\end{document}

The two empty rows are compensated by the two negative spacings.

enter image description here

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4
  • Thanks. That's a good solution, but uses array.
    – implicit_knowledge
    Feb 27, 2015 at 11:52
  • @implicit_knowledge And what's wrong with it? Note that this one ensures correct vertical spacing; the other two solution (which are mostly equivalent) don't.
    – egreg
    Feb 27, 2015 at 11:53
  • In my context, the other ones work because I use the formula as a standalone image, so I don't need to use array. But I see that your solution is "more right" than the others. OK; I changed your solution, because it seems it is the correct thing to do in normal context.
    – implicit_knowledge
    Feb 27, 2015 at 11:56
  • 1
    @implicit_knowledge Then try using \documentclass[varwidth]{standalone} instead of \documentclass{article}: you'll be surprised with Bernard's solution.
    – egreg
    Feb 27, 2015 at 11:59
4

Add some positive vertical spacing before empheq (e.g. \vspace*{\baselineskip}) and add the same amount of negative spacing (e.g. \\[-\baselineskip]) inside empheq.

\documentclass{article}

\usepackage{empheq}

\begin{document}
\vspace*{\baselineskip}
\begin{empheq}[right=\empheqrbrace]{align*}
\\[-\baselineskip]
\dfrac{\dfrac{\dfrac{\dfrac{
    \frac{1}{a} % <-- start with this a
}{a}}{a}}{\vdots}}{a}
\end{empheq}
\end{document}

enter image description here

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2
  • This won't be correctly spaced with respect to the context.
    – egreg
    Feb 27, 2015 at 11:05
  • Thanks. That's a good solution. But Bernard's is even simpler.
    – implicit_knowledge
    Feb 27, 2015 at 11:52
2

A simple solution using \smash within empheq. You may have to make some manual adjustment w.r.t. the above context:

\documentclass{article}

\usepackage{empheq}
\usepackage{lipsum} 

\begin{document}

\lipsum[2]\medskip
\begin{empheq}[right=\empheqrbrace]{align*}
  \dfrac{\dfrac{\dfrac{\dfrac{
    \smash[t]{ \frac{1}{a}} % <-- start with this a
    }{a}}{a}}{\vdots}}{a}
\end{empheq}
\lipsum[2]
\end{document}

enter image description here

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6
  • I also get a different output. The upper part of the brace is exactly vertically in the middle of the number 1.
    – implicit_knowledge
    Feb 27, 2015 at 11:46
  • 1
    Sorry, I mixed in different tentative solutions. I've updated to the correct one, even simpler.
    – Bernard
    Feb 27, 2015 at 11:49
  • Yes, without \vphantom this is better and simpler. It's the easiest solution and renders perfectly now. Thanks!
    – implicit_knowledge
    Feb 27, 2015 at 11:50
  • This has the same defect as karlkoeller's solution: it doesn't space correctly when in context. Try adding \lipsum*[2] before the empheq environment.
    – egreg
    Feb 27, 2015 at 11:52
  • I does work for me because I use it as a standalone image. But if needed in context, egreg's solution should be taken with \array.
    – implicit_knowledge
    Feb 27, 2015 at 11:58

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