# How to typeset inclusion arrow?

I would like to know what is the best way to do an inclusion arrow, using xy or tikz. I know that there is a command for an arrow, like \to, for inclusions, but this is not expansible.

What do you use?

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The mathtools package gives you extansible hook-arrows which some authors use for inclusions:

\documentclass{article}
\usepackage{mathtools}

\begin{document}

$A\xhookrightarrow{} B\qquad A\xhookrightarrow{f\circ g} B\qquad A \xhookrightarrow[(f\circ g)\circ h]{} B$

\end{document}


You can also use \xrightarrow from amsmath if you want an extensible "standard" arrow with super/subscripts:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

$A\rightarrow{} B\qquad A\xrightarrow{f\circ g} B\qquad A \xrightarrow[(f\circ g)\circ h]{} B$

\end{document}


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Thanks so much. – Sigur Aug 8 '12 at 1:53