xypic: is it possible to change the slope of an arrow?

Question

In this diagram, I want arrows from \Delta X~ in the middle of the 2nd row goes to both N\Delta X and (Delta X)~/D\Delta X, how do I do that? (making columns very narrow and draw very fine lattices seems to be a solution, but I wonder if there is an easier way.)

Answer 1

You seem to have inserted that middle arrow in the upper row as part of the center node (you don't show your code, so you're making me guess), since the arrowheads you're using in your \xymatrix are different from the standard arrowheads in latex. If that's true, then you can still replace that upward arrow (which points toward the center of that upper node) into an arrow that points to someplace offset from the center of that upper node. That is, you can replace that arrow with something like the two arrows

\ar[u]+<-2em,-1ex>
\ar[u]+<2em,-1ex>

You should play around with those 2em and 1ex distances until the arrows points where you'd like them to point.

You can also get your \xymatrix arrowheads to match your other arrow heads by loading Xy-pic using the line

\usepackage[all,cmtip]{xy}

and you can have all nodes automatically in displaystyle by following that line with the line

\let\objectstyle=\displaystyle