Is it possible to stack three relations or symbols ontop of one another? Specifically I would like to stack three symbols,
L in order to define a pair of adjoint functors $R:C\to D$ and $C\gets D:L$.
Also, is there a
\rightleftarrow with long arrows? EDIT I actually meant to ask wether there is a version of
\rightleftarrows with long arrows.
I'm not a regular user, so I don't know how to format my question adequately, could someone convert what's inside the dollar so that it appears as latex please?