∀ {F : Type v'} {R : Type u} {A : Type v} {B : Type w} [inst : CommSemiring R] [inst_1 : NonUnitalNonAssocSemiring A]
  [inst_2 : NonUnitalNonAssocSemiring B] [inst_3 : Module R A] [inst_4 : Module R B] [inst_5 : FunLike F A B]
  [inst_6 : NonUnitalAlgHomClass F R A B] (S : NonUnitalSubalgebra R B) (f : F) (x : A),
  x ∈ NonUnitalSubalgebra.comap f S ↔ f x ∈ S