How do I stack more than two arrows in math mode?

The command \rightrightarrows (from amssymb) draws two arrows, one on top of another. How do I get three arrows arranged in a similar fashion? An example of this (and other fancy arrow stackings) appears on page 3 of this paper, for which a source file unfortunately does not seem to be available. Commands like \stackrel and \overset do not size or space things properly.

• I’m rather surprised that there is no package with these symbols. For three arrows there is even a Unicode symbol (which unicode-math exposes as \rightthreearrows). – Caramdir Sep 2 '10 at 9:37

\newcommand\rightthreearrow{%
\mathrel{\vcenter{\mathsurround0pt
\ialign{##\crcr
\noalign{\nointerlineskip}$\rightarrow$\crcr
\noalign{\nointerlineskip}$\rightarrow$\crcr
\noalign{\nointerlineskip}$\rightarrow$\crcr
}%
}}%
}


This is basically how \overbrace works except that it uses a fill and a \vbox instead of a \vcenter.

• You could add some spacing to cause the arrows to not overlap. I didn't even notice it until just now though. – TH. Sep 3 '10 at 8:30
• I think you should use \mathrel, not \mathop for correct spacing (\rightrightarrows are \mathrel). – Hendrik Vogt Dec 17 '10 at 10:38
• @Hendrik: Thanks. Fixed. (I didn't change the picture though.) – TH. Dec 17 '10 at 10:43

Use \substack



You might adjust the spacing using the optional argument, perhaps choose another arrow with a smaller tip if you like.