Module

NormalizationPushforward.lean

Nyll.SchemeTheory.Morphisms.NormalizationPushforward
2 declarations indexed from sourceView source ↗

The structure-sheaf pushforward of relative normalization

The section isomorphisms above affine opens of the original base imply the full structure-sheaf pushforward assertion for the native relative normalization, with no affine or Noetherian hypothesis on the base.

Declarations

AlgebraicGeometry.isIso_c_of_isIso_app_affine_cover

A qcqs morphism whose section maps are isomorphisms on an affine open cover induces an isomorphism of the structure sheaf with its pushforward.

Source context 5 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
open CategoryTheory CategoryTheory.Limits TopologicalSpace
namespace AlgebraicGeometry
universe u v
variable {X S : Scheme.{u}} (f : X ⟶ S)
lemma isIso_c_of_isIso_app_affine_cover [QuasiCompact f] [QuasiSeparated f]
    {I : Type v} (U : I → S.Opens) (hU : ∀ i, IsAffineOpen (U i))
    (hCover : iSup U = ⊤) (hSections : ∀ i, IsIso (f.app (U i))) :
    IsIso f.c
AlgebraicGeometry.Scheme.Hom.isIso_toNormalization_c

The structure sheaf of the native relative normalization is the pushforward of the source's structure sheaf for a universally closed qcqs morphism.

Source context 6 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
open CategoryTheory CategoryTheory.Limits TopologicalSpace
namespace AlgebraicGeometry
universe u v
variable {X S : Scheme.{u}} (f : X ⟶ S)
namespace Scheme.Hom
lemma isIso_toNormalization_c [QuasiCompact f] [QuasiSeparated f]
    [UniversallyClosed f] : IsIso f.toNormalization.c