∀ {R : Type u} {M : Type v} {M₂ : Type w} [inst : Semiring R] [inst_1 : AddCommMonoid M] [inst_2 : AddCommMonoid M₂]
  [inst_3 : Module R M] [inst_4 : Module R M₂] (f : M →ₗ[R] M₂) (x : M × M₂), (x ∈ f.graph) = (x.2 = f x.1)