∀ (Y : AlgebraicGeometry.Scheme) {X Y_1 Z : (CategoryTheory.Over Y)ᵒᵖ} (x : X ⟶ Y_1) (x : Y_1 ⟶ Z),
  AlgebraicGeometry.Scheme.Hom.ker (Opposite.unop X).hom ≤ AlgebraicGeometry.Scheme.Hom.ker (Opposite.unop Z).hom