# Vertical spacing between fractions in matrix environment [duplicate]

When a fraction is used in a matrix environment, not enough vertical space is put between the rows. Wikibooks recommends using the \em command, but this seems like an inelegant solution. Is there an elegant solution?

• It is always best to compose a MWE that illustrates the problem including the \documentclass so that those trying to help don't have to recreate it. Commented Nov 2, 2011 at 23:30
• @PeterGrill I would have, but this seems like such an obvious scenario that an MWE isn't necessary and actually clutters the question. Am I wrong? Commented Nov 2, 2011 at 23:37
• – Werner
Commented Nov 2, 2011 at 23:39
• @Quinn: MWEs are always welcome and definitely encouraged, since subjective views may interpret questions differently.
– Werner
Commented Nov 2, 2011 at 23:41
• Yeah I realize it is not that hard, but anyone who wants to provide a solution will have to create it to test it and if you provide one to start there is less chance of misinterpretations. Commented Nov 3, 2011 at 0:09

One approach is to add extra space between specific lines, with an optional argument to \\:

\left[\begin{matrix}
\frac{1}{2} & \frac{3}{2} \\
\frac{5}{2} & \frac{7}{2}
\end{matrix}\right]


produces

While

\left[\begin{matrix}
\frac{1}{2} & \frac{3}{2} \$6pt] \frac{5}{2} & \frac{7}{2} \end{matrix}\right]  produces • Note that the OP wanted to avoid this approach Commented Nov 3, 2011 at 2:12 • @cmhughes: Hm, I didn't see that in the post. Where was it stated? Commented Nov 3, 2011 at 4:26 • Wikibooks recommends using the \em command, but this seems like an inelegant solution. No big deal though, it gets the job done :) Commented Nov 3, 2011 at 4:48 • OK, I did see that, so I guess my question is... is \em equivalent to \\? Commented Nov 3, 2011 at 4:54 • The Wikibooks link recommends using \\[0.3em] and you used \\[6pt]. The similarity (in my mind) is that both are manual approaches. Commented Nov 3, 2011 at 5:14 If you use an array environment then you can use the command \renewcommand{\arraystretch}{2.5}  and tweak it to whatever you would like. I have loaded the amsmath package to use \dfrac \documentclass{article} \usepackage{amsmath} \begin{document} Default: \[ \left[ \begin{array}{ccc} \dfrac{5}{6} & \dfrac{1}{6} & 0 \\ \dfrac{5}{6} & 0 & \dfrac{1}{6} \\ 0 & \dfrac{5}{6} & \dfrac{1}{6} \end{array} \right]$
\renewcommand{\arraystretch}{2.5}
Stretched:
$\left[ \begin{array}{ccc} \dfrac{5}{6} & \dfrac{1}{6} & 0 \\ \dfrac{5}{6} & 0 & \dfrac{1}{6} \\ 0 & \dfrac{5}{6} & \dfrac{1}{6} \end{array} \right]$
\end{document}

• But isn't this bad because it used array where matrix is more appropriate? Commented Nov 4, 2011 at 15:37
• @Quinn: that's up to you! If you'd prefer to use matrix then have a look at the links that people have posted as comments Commented Nov 4, 2011 at 15:46
• This works for more than two lines as it centers the middle lines.
– Yvon
Commented Mar 17, 2021 at 20:27

In plain-tex format at least, \matrix calls \normalbaselines, which resets the (base)lineskip(limit)'s to normal(base)lineskip(limit)'s. Plain also has a macro called \openup<dimen> which increases the (base)lineskip(limit)'s by given <dimen>.

So it would seem logical to define a macro \openupnormal, which would do the same as \openup, only for normal(base)lineskip(limit)'s:

\catcode@=11
\def\openupnormal{\afterassignment\@penupnormal\dimen@=}

$$\left[ \openupnormal1\jot\matrix{ % inside this group, increase the % normal(base)lineskip(limit)'s by 1 jot {5\over6} & {1\over6} & 0 \cr {5\over6} & 0 & {1\over6} \cr 0 & {5\over6} & {1\over6} \cr } % the group ends here, and so does the effect of \openupnormal \right] \quad \left[ \matrix{ {5\over6} & {1\over6} & 0 \cr {5\over6} & 0 & {1\over6} \cr 0 & {5\over6} & {1\over6} \cr } \right]$$

(Note that there is no \displaystyle in effect in the above fractions, unlike in \dfrac)
• I tried it with LaTeX and no errors. But I suppose you'd write things differently with LaTeX (\makeatletter/\makeatother instead of \catcode's, \frac/\dfrac instead of {x\over y}, \$/\$ instead of  etc. Commented Nov 4, 2011 at 15:48