fact: Definition fmap {T U : Type} (f : T -> U) (F : set_system T) : set_system U := [set P | F (f @^-1` P)].
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed