∀ (Y : AlgebraicGeometry.Scheme) {I J : Y.IdealSheafDataᵒᵖ} (h : I ⟶ J),
  (AlgebraicGeometry.Scheme.IdealSheafData.subschemeFunctor Y).map h =
    CategoryTheory.Over.homMk (AlgebraicGeometry.Scheme.IdealSheafData.inclusion ⋯) ⋯