# Curved arrow in xymatrix going over text

In some notes I took in a lecture, where I was using xymatrix to do the commutative diagrams, I found that a curved arrow beneath the diagram actually crossed over some text. (Ideally, the text should be lowered to accommodate the height of the "equation.") Here's a minimal working example:

\documentclass{minimal}
\usepackage{amsmath,lipsum}
\usepackage[cmtip,all]{xy}
\DeclareMathOperator{\Spec}{Spec}

\begin{document}

$\xymatrix{ \Spec B^G \ar[r] \ar@/_2pc/[rr] & \Spec \widetilde{R} \ar[r] & \Spec R \\ }$

\lipsum[1]

\end{document}


Am I doing something wrong here, or is this a bug? In either case, how do I correct it, in a way simple enough to work when I am taking lecture notes in real time?

-

$\xymatrix{ \Spec B^G \ar[r] \ar@/_2pc/[rr]_{} & \Spec \widetilde{R} \ar[r] & \Spec R }$