Let us consider the following example:

\documentclass{book}
\usepackage[all]{xy}
\begin{document}
$\xymatrix{A\ar[rr] && B}$
\end{document}


This produces

but I want the following arrowhead style using xypic:

How can I do this?

You can obtain something like this

by defining a new direction arrow (requires amssymb)

\newdir{|>}{-<5pt,0pt>{\blacktriangleright}}


MWE:

\documentclass{book}
\usepackage{amssymb}
\usepackage[all]{xy}
\newdir{|>}{-<5pt,0pt>{\blacktriangleright}}

\begin{document}
$\xymatrix{A\ar@{-|>}[rr] && B}$
\end{document}

• May be \llap the \blacktriangleright? – Manuel Feb 5 '15 at 11:10
• @Manuel Have you tried it with \llap? It doesn't look good. – karlkoeller Feb 5 '15 at 11:38