I sometimes uses ~
to adjust space between symbols. Now I want to add some vertical space which play similar role, how do I do that?
(It's not about controlling space between lines, but just add some space, the real problem is like this: I put \displaystyle \int X
, and X
at the same time in an xymatrix
, then the arrows are of different length because it thinks \displaystyle \int X
occupied more vertical space than X
.
)