∀ {A : Type u_1} {σ : Type u_2} [inst : CommRing A] [inst_1 : SetLike σ A] [inst_2 : AddSubgroupClass σ A] (𝒜 : ℕ → σ)
  [inst_3 : GradedRing 𝒜] (f : A) {m : ℕ},
  f ∈ 𝒜 m → 0 < m → CategoryTheory.IsIso (AlgebraicGeometry.ProjectiveSpectrum.Proj.toSpec 𝒜 f)