∀ {R : Type u_1} {M : Type u_2} [inst : SMul R M] {N : Type u_3} {F : Type u_4} [inst_1 : SMul R N]
  [inst_2 : FunLike F M N] [MulActionHomClass F R M N] (f : F) {r : R},
  Function.Injective ⇑f → IsSMulRegular N r → IsSMulRegular M r