I've been using nearly identical LaTeX code to typeset several adjoint triples. In all but one the arrowheads point as they should, but one of them is messed up. Here's a minimal working example, but with one catch: it displays correctly. (This isn't the case in my long manuscript. For some reason, this is the only diagram that doesn't display properly.)
\documentclass{article}
\usepackage{amsmath}
%xymatrix
\usepackage[all,pdftex, cmtip]{xy}
\newdir{ >}{{}*!/-10pt/@{>}}
\newdir{> }{{}*!/10pt/@{>}}
\begin{document}
\[\xymatrix{
\mathsf{C} \ar[r]|U
& \mathsf{D} \ar@/^3ex/[l]^R_{\perp} \ar@/_3ex/[l]_L^\perp
}\]
\end{document}
The messed up arrowhead is the one on the arrow labeled $L$. In my version, it points south-east. Can I add some code to force the top arrowhead to point south-west?
\Cc
? Please make your code compilable. If this code does not show the falsy output, we can not help you. You have to minimize your "long manuscript" until you find the culprit part and show it to us. If this MWE is supposed to display correctly, we would have to guess what your actual problem is. – LaRiFaRi Jan 25 '16 at 16:31