# How to do multiple columns of multiline braces in LaTeX?

Just like cases environment, with a 2-line (or more) big curly brace to the left of some short equations - but I want to have 3 or 4 columns of equations across the page, each with left-brace. So I can't have the brace outside the environment, I don't think, like the single-big-left-brace solutions I've seen with aligned/array/cases etc. (Imagine 3 or 4 uses of 'cases' environment on a page, each with a large brace to the left of 2 or 3 short equations. What I want is like that, but with the cases/blocks 'stacked' horizontally instead of vertically.)

Sorry, if this has already been asked; I couldn't find it on here or online, and can't think how to do it. I just heard about multicol, maybe I'll have to use that, but it's surprising there seems no LaTeX/ams way of doing it. Thanks.

Edit: Ive been asked for an image. I tried without success, then I read that new users like me can't post them. Hopefully what I wrote is clear enough.

• Without an MWE, an image of expected outcome would really help. Pen and paper is really underestimated. – Runar Jul 6 '16 at 6:56

You also can use dcases from mathtools in an align or alignat environment:

\documentclass{article}
\usepackage{mathtools}

\begin{document}

\begin{alignat*}{3}
& \begin{dcases}
x = 1\\
y = 2 \\
z = 8
\end{dcases}
x = t\\
y = 2t \\
z = 8t
\end{dcases}
x =2 t\\
y = 5-t \\
z = t²
\end{dcases}
\end{alignat*}

\end{document} Maybe using David Carlisle's blkarray package?

\documentclass{standalone}
\usepackage{blkarray}
\begin{document}
\begin{blockarray}{\{l\{l\{l}
$x = 1$ & $x=t$ & $x=2t$ \\
$y = 2$ & $y = 2t$ & $y = 5-t$ \\
$z = 8$ & $y=3t$ & $z=t^2$
\end{blockarray}
\end{document} • (+1) Maybe you might play with the spacing between columns with @{some space}? – Bernard Jul 6 '16 at 8:44

My modified/stripped down plain-math-mode version of Bernard's alignat*/dcases answer, which (surprisingly) produces an identical result on my screen. Though his will obviously also align with further rows. (I'm using wordpress quicklatex)

$\begin{cases} x = 1\\ y = 2 \\ z = 8 \end{cases} \quad \begin{cases} x = t\\ y = 2t \\ z = 8t \end{cases} \quad \begin{cases} x =2 t\\ y = 5-t \\ z = t^2 \end{cases}$

• It should not be quite the same, since I use a double emspace between the cases, and you use one. You'll see a serious difference using \frac{a}{b} or \int_a^b, say. The d from dcases is for \displaystyle. – Bernard Jul 6 '16 at 15:01