∀ {A : Type u_1} {σ : Type u_2} [inst : CommRing A] [inst_1 : SetLike σ A] [inst_2 : AddSubmonoidClass σ A] (𝒜 : ℕ → σ)
  [inst_3 : GradedRing 𝒜] {f : A} {I : ProjectiveSpectrum 𝒜},
  I ∈ (ProjectiveSpectrum.zeroLocus 𝒜 {f})ᶜ ↔ f ∉ I.asHomogeneousIdeal