# Delimiters -- appropriate usage

What is the appropriate LaTeX when I do not want a closing right bracket? Alternatively, should I setup the left bracket differently?

\begin{align*}
r_{sj} &=
\left\{ \begin{array}{lc}
1 & \text{if $Y_j$ is observed in $s$} \\
0 & \text{if $Y_j$ is missing in $s$}
\end{array} \right
\end{align*}


Here, I do not wish to have \right\} in the text.

But I get a missing delimiter error on compiling

• If you don't want a closing "fence" symbol -- curly brace, square bracket, round parenthesis, angle bracket, vertical bar, whatever -- simply write \right. (note the "dot" after \right). As you've observed, \right by itself throws a syntax error.
– Mico
Mar 24 '17 at 21:40
• in general you can use . but amsmath has a specific cases environment to produce this kind of display, which adds the { automatically Mar 24 '17 at 21:46

For this kind of thing there is the cases environment. If the second columns primarily consists of text, you might want to use cases* from mathtools. If you had some other construction, where cases does not apply, you can insert an “empty” delimiter using . as in \right..

\documentclass{article}

\begin{document}

\begin{equation*}
r_{sj} =
\begin{cases*}
1 & if $Y_j$ is observed in $s$ \\
0 & if $Y_j$ is missing in $s$ \\
\end{cases*}
\end{equation*}

\end{document}


• For other constructions, there's also the solution of the empheq package (which loads mathtools) and its eponymous environment. Mar 24 '17 at 23:03