# [Xy-pic] Re: XY pic

**Kristoffer H Rose
**
krisrose@us.ibm.com

*Sun, 15 Dec 2002 20:50:36 -0500*

Dear Irene,
First: did you try to *just* use \xymatrix@=35pt{...} (or better still
something like @C+2em) without @1? If this is not sufficient then you may
need the cell mutation hack...
The idea is this:
1. Give the cells that get squeezed an extra large margin.
2. Insert mutation code first in matrix to undo the extra margin before the
arrows get added!
Here's how (hope it works :)
$$
\xymatrix{
X^2_0 \times_X {}_0 X^{k+1}
\POS"1,2"*---\frm{}="1,2" %% REDUCE MARGIN OF "1,2" WITH THREE UNITS.
\ar[r]^-{f^2 \times \id}
\ar[d]_-{q_0}
&*++++{Y^2_0 \times_Y {}_0 X^{k+1}} %%% MEASURE WITH FOUR TIMES STANDARD
MARGIN
\ar[r]^-{\id \times f^{k+1}}
\ar[d]_-{q'_0}
& Y^2_0 \times_Y {}_0 Y^{k+1}
\ar[d]_-{q''_0}\\
X \ar[r]_-\id
& Y \ar[r]_-f
& Y
}
$$
Note that mutation only works on the absolute "R,C" names of cells as those
are used by the Xy-matrix code internally.
Enjoy,
Kristoffer
__
Kristoffer H Rose, ph.d. <krisrose@us.ibm.com> +1(914)784-7642/fax:6324
IBM T. J. Watson Research Center, 19 Skyline Dr, Hawthorne NY 10532