6

I have a set of equations where some are coupled with a brace and some text. I want all the equations aligned. Something like the following ASCII art:

 S = LR

 L = Ls                |  for s in {a, b}
Rs = sR  /

I tried this:

\begin{align*}
S &= LR \\
\left.
\begin{gather*}
L &= L_s\\
R_s &= sR
\end{gather*}
\;\;\right\}\;\;\text{for } s \in \{a, b\}\\
\end{align*}

But it doesn't compile (because & is not expected inside a gather* environment). Is it possible to do this?

David Carlisle
  • 757,742
Max
  • 195

1 Answers1

10

A simple way would be:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{align*}
S &= LR \\
\begin{split}
L &= L_s\\
R_s &= sR
\end{split}\quad\Bigg\}\,\,\text{for } s \in \{a, b\}
\end{align*}

\end{document}

enter image description here

David Carlisle
  • 757,742
Gonzalo Medina
  • 505,128
  • The only thing I'd change is to use \bigg instead of \Bigg. Of course, that's entirely subjective. :-) – Mico Apr 24 '12 at 13:39
  • In my actual document, there are more than two equations inside the brace, so \Bigg is not big enough. I guess I have to mess around with vphantoms and the like to get bigger? – Max Apr 25 '12 at 08:43
  • @Max: you can then use stretchable delimiters and a rule with no width and desired height: \begin{align*} S &= LR \\begin{split} L &= L_s\R_s &= sR\T_s &= sT \end{split} \quad\left.\rule{0pt}{1.5\baselineskip}\right\rbrace\,\,\text{for } s \in \{a, b\} \end{align*} (sorry about the poor code formatting, but comments are not the best place to write code). – Gonzalo Medina Apr 25 '12 at 13:35
  • Is there any way where the size of the brace is automatically calculated? – Wauzl Apr 29 '14 at 18:49