# [texhax] \ar

Sun Feb 3 01:34:10 CET 2008

On Tue, Jan 29, 2008 at 06:06:26AM -0800, sarah yasseen wrote:
> "A \ar {->}[r]&B"  gives an arrow that begins at A and ends at B.

Don't know what \ar is, but...

> How to make that arrow starts exactly from A (touches A), i.e., no
> space between A and the arrow?

It's not possible to do this in a generic way, so that it works with
any glyphs, not just A and B, because TeX doesn't know anything about
the actual glyph shapes, it only knows about glyph boxes (which are
rectangular).  So the only way to do this is to insert spacing tweaks,
something like:

A \!\!\! \rightarrow \!\!\!B\cr

\! is a predefined (by plain TeX) negative skip macro for the math
mode.  You should define skip macros for math mode in terms of mu's,
not pt's, like this:

\def\myskip{\mskip-5mu}

HTH,
Oleg