\setlength\arraycolsep{1pt}
{}_3 F_2\left(\begin{matrix}a& &b& &c\\&d&
&e&\end{matrix};z\right)
That tightens up the spacing quite a bit. I made a hypergeometric macro previously, but it doesn't support the ;z
, unfortunately.
\newcommand*\pFq[2]{{}_{#1}F_{#2}\genfrac[]{0pt}{}}
Then you use \pFq{3}{2}{a,b,c}{d,e}
. (Or replace the commas with any other sort of spacing you want.) I was fairly happy with that.
Edit: Actually, how about something like this?
\newcommand*\pFqskip{8mu}
\catcode`,\active
\newcommand*\pFq{\begingroup
\catcode`\,\active
\def ,{\mskip\pFqskip\relax}%
\dopFq
}
\catcode`\,12
\def\dopFq#1#2#3#4#5{%
{}_{#1}F_{#2}\biggl[\genfrac..{0pt}{}{#3}{#4};#5\biggr]%
\endgroup
}
Change \pFqskip
to whatever spacing you want between the elements. You use it like
\pFq{3}{2}{a,b,c}{d,e}{z}
I got the definition below after some tinkering. It seems to look fine at any size.
\documentclass[a4paper,12pt]{article}
\pagestyle{empty}
\usepackage{mathtools}
\def\multiset#1#2{\ensuremath{\left(\kern-.3em\left(\genfrac{}{}{0pt}{}{#1}{#2}\right)\kern-.3em\right)}}
\begin{document}
Consider an inline multiset, \multiset{n}{k}, or a displayed one,
\[ \multiset{n}{k}, \]
or perhaps even a displayed one with something big up- and downstairs,
\[\multiset{
{\displaystyle \sum_{j=1}^n n^j}}
{{\displaystyle \sum_{j=1}^n (-1)^j n^j}}_{n \text{ even}}.
\]
\end{document}
Best Answer
As Sigur mentioned in the comments you could use
amsmath
's\xrightarrow{•}
.Unfortunately this leads to a quite short arrow:
There are multiple options to get a longer arrow. You could just add some space at the left and right. But this still leads to differently long arrows depending on the overset content.
To prevent this you could use
\overset{•}{•}
combined with a\longrightarrow
.But in this case imho the arrow is still a little bit short. So the best way is probably to define a custom
\xrightarrow
with a fixed width like this. Change the predefined value2em
to get a shorter or longer arrow.Which can then easily be used like this: