# Text hypenation inside array-typed environment

I'm trying to write a cases or array environment, inside display mode, with some long line of text. The thing is I can't achieve a linebreak. I know for certain that array won't allow this. I also know that a "brute force" solution can be achieved easily. However, before forcing a linebreak where I think it would be nice, I thought about asking here, not just for aesthetics but for learning too.

Here's the code I'm using

\ProvidesPackage{mystyle}
\usepackage[spanish]{babel} %Idioma
\usepackage[utf8]{inputenc} %Codificacion
\usepackage[T1]{fontenc}    %Para que use las formas vectoriales de las fuentes
%\usepackage{lmodern}       %Cambia Computer Modern por Latin Modern
\usepackage{mathtools}      %Paquete matemático general
\usepackage{hyperref}       %Links dinámicos en los capítulos y demás
\usepackage{cancel}         %Para tachar expresiones matemáticas
\usepackage{graphicx}       %Importar imágenes

\begin{align}
\varepsilon_{\underbrace{ijl\hdots}_{n \text{ índices}}} =
\begin{cases}
0 & \text{si hay dos índices iguales}   \\
1 & \text{si todos los índices son distintos y son una permutación par de $1,2,\hdots n$ }   \\
-1 & \text{si todos los índices son distintos y son una permutación impar de $1,2,\hdots n$ }
\end{cases}
\end{align}


Here the output:

It's very isolated from the rest of the text so it's impossible to take a screenshot where you can see the margins, but I think the equation number will suffice.

So, the thing is, is there an array-typed environment that allows automatic hyphenation?

Set the contents <stuff> inside a \parbox[t]{<len>}{<stuff>} of fixed width <len> that is [t]op-aligned:

\documentclass{article}
\usepackage[spanish]{babel} %Idioma
\usepackage[utf8]{inputenc}
\usepackage{amsmath}

\begin{document}

\begin{align}
\varepsilon_{\underbrace{ijl\hdots}_{n \text{ índices}}} =
\begin{cases}
0 & \text{si hay dos índices iguales}   \\
1 & \parbox[t]{.6\linewidth}{si todos los índices son distintos y son una permutación par de $1,2,\hdots n$ }   \\
-1 & \parbox[t]{.6\linewidth}{si todos los índices son distintos y son una permutación impar de $1,2,\hdots n$ }
\end{cases}
\end{align}

\end{document}

• Thanks a lot. This is the kind of thing I still have to read about and learn, using boxes, minipages, etc. Just one more question, is there a command that references to the space it still has up to the margin? I mean, some way to tell LaTeX this will have 0.6 of the width I have until the margin. With that, it would definately be the most elegant solution. – Sabian May 29 '14 at 2:39