[Tex/LaTex] Triangle commutative diagram with xymatrix

Question

I'm using the xymatrix package (which I think is more friendly than tikz package), and I've been trying to do a simple triangle diagram with a circle arrow in the middle. I mean, I've done this one:

\documentclass{article}
\usepackage[all]{xy}
\begin{document}
$\xymatrix
   { & \mathcal{L} \ar[dl]_{\pi_j} \ar[dr]^{\pi_i} & \\
     G_j \ar[rr]_{\pi_i^j} & & G_i
   }
$
\end{document}

and I want to add a circle arrow in the middle. I've tried to add rows, but the diagonal arrows became crazy, and the result is awful.

Answer 1

Like this?

\documentclass{article}
\usepackage[all]{xy}
\begin{document}
$\xymatrix
   { & \mathcal{L} \ar[dl]_{\pi_j} \ar[dr]^{\pi_i} \ar[d]|-{\circ} & \\
     G_j \ar[rr]_{\pi_i^j} & & G_i
   }
$
\end{document}