As denoted in XY-pic's user guide, "Each label is placed perpendicular to the arrow at the point halfway between the centers of the base and target objects." In order to center the label at the middle of the arrow instead, one must insert - after the ^ or _. The difference is quite clear in the following example:
\documentclass{amsart}
\usepackage[all]{xypic}
\begin{document}
$$\xymatrix{A\times B\times C \ar[r]^f & D}$$
$$\xymatrix{A\times B\times C \ar[r]^-f & D}$$
\end{document}
In the first xy-matrix (default centering), the function label $f$ will be shoved back to the left of the arrow, completely obscured. In the second xy-matrix (alternative centering), the function label $f$ is appropriately, or more naturally, placed in the middle of the arrow.
After using XY-matrix for a while, I've found that I insert the command - more often than I omit it. My question is the following:
Is there a way to set this alternative centering feature as the default label position?
Being rather TeX-nologically inexperienced, I couldn't find any documentation on a solution.
$$...$$in LaTeX, see http://tex.stackexchange.com/questions/503/why-is-preferable-to – egreg Sep 06 '12 at 14:44-. And as far as$$...$$is concerned, I would agree with Harrold's comment of the accepted answer; I'm perfectly fine with the convenience of using$$...$$while aware of its (very rare) mishaps. I don't see why one should be forced to use one code over another. – Dustin Tran Sep 06 '12 at 15:04$$, we can talk again when some submission of yours will be rejected because not conforming with the journal style that uses left aligned equations. :) – egreg Sep 06 '12 at 15:11-would otherwise misalign them. And about the$$...$$issue, it's certainly not hard to replace them should the need arise; as I said, it's simply more convenient for me, with syntax highlighting and when live-TeXing seminars or lectures. Regardless, I'm still crossing my fingers for a solution! – Dustin Tran Sep 06 '12 at 15:29