∀ {X : AlgebraicGeometry.Scheme} {U : X.AffineZariskiSite} {S : CategoryTheory.Sieve U},
  S ∈ (AlgebraicGeometry.Scheme.AffineZariskiSite.grothendieckTopology X) U ↔
    Ideal.span (AlgebraicGeometry.Scheme.AffineZariskiSite.sectionsOfPresieve S.arrows) = ⊤