How can I write multiple lines in a subscript?

Question

Is there a way to force a line break inside a math mode text?

My example:

\[
  \underbrace{....}_\text{Some long text that should be multiline}
\]

Trying

\text{Some long text that\\ should be multiline}

Didn't do the trick.

Answer 1

You can use the \substack command, from the amsmath package, just like \text.

\[
 \underbrace{....}_{\substack{\text{Some long text that}\\\text{should be multiline}}}
\]

Answer 2

• \substack, mentioned by Carsten, probably fits best to your \underbrace because of the centered alignment.

• subarray is similar but offers customizable alignment:

Example:

\[
 \underbrace{....}_{\begin{subarray}{l}\text{Some  long text that}\\
    \text{should be multiline}\end{subarray}}
\]

• \parbox also works in math mode. You could use a font size command inside.

Answer 3

\documentclass[11pt]{article}
\usepackage{amsmath}

\newcommand\myText[1]{\text{\scriptsize\tabular[t]{@{}l@{}}#1\endtabular}}

\begin{document}

\[
  \underbrace{....}_\myText{Some long text that\\ should be multiline}
\]

\end{document}

Answer 4

Another possibility:

\[
 \underbrace{some equation}_{\text{Some long text that}\atop\text{should be multilined}}
\]

Answer 5

A simple \parbox with a certain width should also do.

\documentclass[11pt]{article}
\usepackage{mathtools}   % loads »amsmath«

\begin{document}
  \[
    \underbrace{ax^3+bx^2+cx+d}_{\text{\parbox{10em}{Some text that should be multi-lined}}}
  \]
\end{document}