How to make longer arrows in math-mode?

Question

My question is relative to the following problem; in math-mode, I want to write an inclusion

$C_p^\mathcal{U}\hookrightarrow C_p(X)$

However, this is insuficient, since I have written a long document in which every arrow (in math-mode) has been either \longrightarrow or \longmapsto, making this presentation pretty awkward. However, I would like to know if there is a way to implement this long hooked arrow in math-mode, or what should be done to be able to use this symbol between text.

Thanks in advance for your help.

Answer 1

Use \xhookrightarrow from mathtools, e.g.

\documentclass{article}
\usepackage{mathtools}
\begin{document}
$C_p^\mathcal{U}\hookrightarrow C_p(X)$

$C_p^\mathcal{U}\xhookrightarrow{\quad} C_p(X)$
\end{document}

Here, \quad is just an example. This is an extensible arrow, which will adjust its size to what it written above (or underneath) it, even if this is just some space like \quad.

Answer 2

I can add an answer with the use of the old-arrows package with the option [new]. The old-arrows package provides additional commands for new types of arrows.

\documentclass[a4paper,12pt]{article}
\usepackage[new]{old-arrows}
\usepackage{amssymb}

\begin{document}
(\texttt{long hookrightarrow})
$
C_{p}^{\mathcal{U}} \varlonghookrightarrow C_{p}(X)
$

(\texttt{short hookrightarrow})
$C_{p}^{\mathcal{U}} \varhookrightarrow C_p(X)$
\end{document}