# Single bracket grouping lines of text

This can be done by using the gathered environment, like this example with a curly bracket (brace):

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath}

\begin{document}

$\left\{ \begin{gathered} \mathrm{x} \\ \mathrm{y} \\ \mathrm{z} \\ \end{gathered} \right.$
$\left\{ \begin{gathered} x \\ y \\ z \\ \end{gathered} \right.$