[Xy-pic] arrows to round objects

[Jürgen Koslowski]

Hello,

The issue of arrows between round objects being too short was solved
a while ago, but apparently only in the the matrix environment.  When
using "plain" xypic, the problem still persists.  Here is a toy example:

\[\xymatrix{
  {a_0}\drop\cir<8 pt>{}
		\ar@(ur,ul)[]_{a}
  }
\]

\[\xy;<20 pt,0 pt>:
  (0,0)*+{a_0}*{\cir<8 pt>{}}="A",
   \ar@(ur,ul)_{a}"A";"A"
 \endxy
\]

On the other hand, these kinds of loops do not grow in size when the
object gets bigger, so I'd rather use something like

\[\xy;<20 pt,0 pt>:
  (0,0)*+{a_0}*{\cir<8 pt>{}}="A",
   \ar@(ur,ul)_{a}"A"!UR;"A"!UL
 \endxy
\]

But I do not know how to achieve this in the matrix environment (ie,
address specific corners of the objects as endpoints of arrows).

On a related note: has there been any progress on the issue raised in 
remark 23p in the reference guide, p. 42?  This concerns the restriction
that the directions d_i in @(d_1,d_2) themselves cannot contain
parentheses, hence are restricted to the 8 diagonals.

-- Jürgen

-- 
Juergen Koslowski               If I don't see you no more on this world
ITI, TU Braunschweig               I'll meet you on the next one
koslowj at iti.cs.tu-bs.de               and don't be late!
http://www.iti.cs.tu-bs.de/~koslowj      Jimi Hendrix (Voodoo Child, SR)