∀ {F : Type u_3} {R : Type u_4} {A : Type u_1} {B : Type u_2} [inst : CommSemiring R]
  [inst_1 : NonUnitalNonAssocSemiring A] [inst_2 : Module R A] [inst_3 : NonUnitalNonAssocSemiring B]
  [inst_4 : Module R B] [inst_5 : FunLike F A B] [NonUnitalAlgHomClass F R A B] (ϕ ψ : F), 0 ∈ {a | ϕ a = ψ a}