∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] {D : Type u_2}
  [inst_1 : CategoryTheory.Category.{v_2, u_2} D] (J : CategoryTheory.GrothendieckTopology C)
  (K : CategoryTheory.GrothendieckTopology D) (G : CategoryTheory.Functor C D)
  [CategoryTheory.Functor.IsDenseSubsite J K G] {U V : C} (f₁ f₂ : U ⟶ V),
  G.map f₁ = G.map f₂ → CategoryTheory.Sieve.equalizer f₁ f₂ ∈ J U