[Xy-pic] Vertical alignment in xymatrix

[Michael Abbott]

> > Silence from whom ?
> Sorry, I think I got too impatient!
>
> That's understandable. Dismissing my ludicrous suggestions as non-solutions
> isn't! ;)

I think the issue is this:

All the solutions so far seem to involve hacking the math text so that its
height and depth match up so that the resulting text is symmetrical around
the centre-line.

Is this analysis correct?

In particular, is it really the case that xy just throws away the baseline
of the text when converting it into a box?  That's really what I'm trying
to get at, and why I was so dismissive about your answers (I do apologise;
I didn't mean to be rude).

If this really is the case, and this is actually a deficiency in xy, how
difficult will it be to create an option which computes the xy box with
the centre in the *right* place?