# [Xy-pic] Math fonts

Michael Abbott michael at araneidae.co.uk
Tue May 6 09:05:53 CEST 2003

> For example when running LaTeX on the command
> $\xymatrix{ \mathbb{R} \ar[r]^{d} & \mathbb{R} }$
>
> I get the following error (twice):
>
> ! You can't use \spacefactor' in math mode.
> \@ ->\spacefactor
>                    \@m
> l.19 \xy@{\save }{\save@ }
>                            %

This is very odd: when I try the same test in my document it works fine.

Can you try finding the smallest document which reproduces the problem?
It's most likely that something else you're including is throwing things
off.

Certainly the following works for me:

\documentclass{article}
\usepackage[matrix,arrow]{xy}
\usepackage{amssymb} % For \mathbb
\begin{document}
$\xymatrix{ \mathbb{R} \ar[r]^{d} & \mathbb{R} }$
\end{document}

See what you need to add to get the behaviour you see.
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