[Xy-pic] Re: aligned text over arrows in xypic

[R.P.I. Lewis]

Saul Lubkin <lubkin@math.rochester.edu> writes:

> HOWEVER, there's STILL aproblem, with the xymatrix form -- the one that's
> real easy to use!


> It didn't come out the same!  The \xygraph form worked perfectly -- not
> so, for the \xymatrix.  Happily, text on the slanty arrow was still
> aligned with the arrow, as in the \xygraph version; but it didn't appear
> above the arrow; it went right through it!

I too see this problem with 

\xymatrix @C=4pc @R=3pc{%
& & B\\
A \ar [rru]^*[@]=0+!\txt{restriction of $\iota$}
}

However moving the `default margins' modifier (+) to the front and
adding the `do not centre' (!) to the end does work:

\xymatrix @C=4pc @R=3pc{%
& & B\\
A \ar [rru]^*+[@]=0!\txt{restriction of $\iota$}
}

If you swap + and ! you get the text almost below the arrow (but i
dont know why)!