Dear Ross! Last night I found much more elegant (obvious?) Xy-pic solution to that problem: \entrymodifiers={+!!<0pt,\the\fontdimen22\textfont2>} See some examples at http://www.mccme.ru/~vadim/examples/test.pdf or just try \xymatrix{\widetilde W \ar[r] & W} with/without it. I wonder, isn't it the desired default behavior for xy-matrices? Yours, Vadim