fact: Definition prl_map_compat S u F:= [/\ fgraph u, domain u = psI S, forall i, inc i (domain u) -> function_prop (Vg u i) F (Vg (psE S) i) & forall i j, gle (psr S) i j -> Vg (psf S) (J i j) \co (Vg u j) = Vg u i].
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)