Few hours ago I have added my answer for this question How to make a math diagram on LaTex?
\documentclass[12pt]{standalone}
\usepackage[all,cmtip]{xy}
\usepackage[bb = boondox]{mathalfa}
\begin{document}
\xymatrix@R=.6pc@C=.6pc
{ & \mathbb{F} \ar[dl]_{\scriptscriptstyle\mu} \ar[dr]^{\scriptscriptstyle\nu} & \\
\mathbb{P} & & \mathbb{M}
}
\end{document}
but the labels are a little too far from the arrows. I have not found in the manual what I am looking for. Is there a way to bring the labels closer to the arrows?
\xymatrix@R=.6pc@C=.6pc { & \mathbb{F} \ar[dl]_{\scriptscriptstyle\mu\!\!} \ar[dr]^{\!\!\scriptscriptstyle\nu} & \\ \mathbb{P} & & \mathbb{M} }