# bending xypic arrow head is inconsistently oriented

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?

• What is \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
• Is the problem related to this question? – Arun Debray Jan 25 '16 at 17:02
• Wow. I mean yes. Though embarrassingly it wasn't until I saw the name at the end (after reading the entire post) that I realized that I'd asked the question. – Emily Riehl Jan 25 '16 at 20:38
• I now have a circular problem because I just commented out newtxmath to fix a problem with font sizing that was affecting the display of a blackboard bold capital Delta. – Emily Riehl Jan 25 '16 at 20:39
• Update: following Arun's suggestion on the original post, I added a small amount of space \, after the \mathsf{C} and that solved the problem. Thanks Arun! – Emily Riehl Jan 25 '16 at 20:44

In case you did not know the package tikz-cd: Here is an implementation of what you want with it.

% arara: pdflatex

\documentclass{amsbook}
\usepackage{tikz-cd}
\tikzset{% taken from http://tex.stackexchange.com/a/143131
,no line/.style={%
,draw=none
,commutative diagrams/every label/.append style={/tikz/auto=false}
}
}
\newcommand*{\cC}{A}

\begin{document}
$\begin{tikzcd} \cC \arrow{r}[description,name=U]{U}\arrow[bend left=40]{r}[name=L]{L} & D \arrow[bend left=40]{l}[name=R]{R} \arrow[from=R, to=U, no line, pos=.65]{}{\perp}\arrow[from=L, to=U, no line, pos=.65]{}{\perp} \end{tikzcd}$
\end{document}


• Thanks for this. I have a temporary fix using tikz-cd, but I'd prefer to solve the problem in xypic for global consistency of style. (All of the other diagrams are drawn in xypic.) – Emily Riehl Jan 25 '16 at 20:40