Module

RecoveredPullback.lean

Nyll.SchemeTheory.Gluing.RecoveredPullback
23 declarations indexed from sourceView source ↗

Actual recovered local charts and overlap maps after arbitrary base change.

Declarations

AlgebraicGeometry.Scheme.Cover.swappedPullbackCover

The pulled-back cover with charts in the order used by Over.pullback.

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
def swappedPullbackCover : Y.OpenCover
AlgebraicGeometry.Scheme.Cover.gluingLocalOver

A local model viewed as a scheme over the original base.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def gluingLocalOver (i : 𝒰.I₀) : Over X
AlgebraicGeometry.Scheme.Cover.gluingChartOver

An open chart viewed as a scheme over the original base.

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def gluingChartOver (i : 𝒰.I₀) : Over X
AlgebraicGeometry.Scheme.Cover.gluingLocalStructure

The structure map from a local model to its open chart.

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def gluingLocalStructure (i : 𝒰.I₀) : gluingLocalOver 𝒰 M i ⟶ gluingChartOver 𝒰 i
AlgebraicGeometry.Scheme.Cover.gluingOverlapOver

The overlap of a local model with a second open chart.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def gluingOverlapOver (ij : 𝒰.I₀ × 𝒰.I₀) : Over X
AlgebraicGeometry.Scheme.Cover.gluingOverlapFirst

The first projection from a local overlap to its model.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def gluingOverlapFirst (i j : 𝒰.I₀) : gluingOverlapOver 𝒰 M (i, j) ⟶ gluingLocalOver 𝒰 M i
AlgebraicGeometry.Scheme.Cover.gluingOverlapSecond

The second projection from a local overlap to its open chart.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def gluingOverlapSecond (i j : 𝒰.I₀) : gluingOverlapOver 𝒰 M (i, j) ⟶ gluingChartOver 𝒰 j
AlgebraicGeometry.Scheme.Cover.overPullback_product_isPullback

The literal pullback of a relative product is the product over the new base.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
theorem overPullback_product_isPullback {P A C : Over X}
    (d : P ⟶ A) (r : P ⟶ C) (h : IsPullback d.left r.left A.hom C.hom) :
    IsPullback ((Over.pullback ψ).map d).left ((Over.pullback ψ).map r).left
      ((Over.pullback ψ).obj A).hom ((Over.pullback ψ).obj C).hom
AlgebraicGeometry.Scheme.Cover.recoveredPullbackOverlap_isPullback
Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
theorem recoveredPullbackOverlap_isPullback (i j : 𝒰.I₀) :
    IsPullback ((Over.pullback ψ).map (gluingOverlapFirst 𝒰 M i j)).left
      ((Over.pullback ψ).map (gluingOverlapSecond 𝒰 M i j)).left
      ((Over.pullback ψ).obj (gluingLocalOver 𝒰 M i)).hom
      ((Over.pullback ψ).obj (gluingChartOver 𝒰 j)).hom
AlgebraicGeometry.Scheme.Cover.recoveredPullbackLocalModel

The pulled-back local model over its pulled-back chart.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def recoveredPullbackLocalModel (i : 𝒰.I₀) : Over ((swappedPullbackCover ψ 𝒰).X i)
AlgebraicGeometry.Scheme.Cover.recoveredPullbackLocalModelIso

The canonical iterated-pullback comparison for the local model.

Source context 6 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
def recoveredPullbackLocalModelIso (i : 𝒰.I₀) :
    recoveredPullbackLocalModel ψ 𝒰 M i ≅
      (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i)
AlgebraicGeometry.Scheme.Cover.recoveredPullbackLocalIso

The given local recovery transported to the standard pullback chart.

Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
def recoveredPullbackLocalIso (i : 𝒰.I₀) :
    recoveredPullbackLocalModel ψ 𝒰 M i ≅
      (Over.pullback ((swappedPullbackCover ψ 𝒰).f i)).obj Z
AlgebraicGeometry.Scheme.Cover.recoveredPullbackChartMap

The recovered chart map into the original object after base change.

Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
def recoveredPullbackChartMap (i : 𝒰.I₀) :
    ((Over.pullback ψ).obj (gluingLocalOver 𝒰 M i)).left ⟶ Z.left
AlgebraicGeometry.Scheme.Cover.recoveredPullbackChartCover

The open cover supplied by the recovered local models.

Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
def recoveredPullbackChartCover : Z.left.OpenCover
AlgebraicGeometry.Scheme.Cover.recoveredPullbackChartMap_isOpenImmersion
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackChartMap_isOpenImmersion (i : 𝒰.I₀) :
    IsOpenImmersion (recoveredPullbackChartMap ψ 𝒰 M Z e i)
AlgebraicGeometry.Scheme.Cover.recoveredPullbackChartMap_isPullback
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackChartMap_isPullback (i : 𝒰.I₀) :
    IsPullback ((Over.pullback ψ).map (gluingLocalStructure 𝒰 M i)).left
      (recoveredPullbackChartMap ψ 𝒰 M Z e i)
      (((Over.pullback ψ).obj (gluingChartOver 𝒰 i)).hom) Z.hom
AlgebraicGeometry.Scheme.Cover.recoveredPullbackChartMap_structure
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackChartMap_structure (i : 𝒰.I₀) :
    recoveredPullbackChartMap ψ 𝒰 M Z e i ≫ Z.hom =
      ((Over.pullback ψ).obj (gluingLocalOver 𝒰 M i)).hom
AlgebraicGeometry.Scheme.Cover.recoveredPullbackOverlapTransfer

The map from a recovered overlap to its second local model.

Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
def recoveredPullbackOverlapTransfer (i j : 𝒰.I₀) :
    ((Over.pullback ψ).obj (gluingOverlapOver 𝒰 M (i, j))).left ⟶
      ((Over.pullback ψ).obj (gluingLocalOver 𝒰 M j)).left
AlgebraicGeometry.Scheme.Cover.recoveredPullbackOverlapTransfer_structure
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackOverlapTransfer_structure (i j : 𝒰.I₀) :
    recoveredPullbackOverlapTransfer ψ 𝒰 M Z e i j ≫
      ((Over.pullback ψ).map (gluingLocalStructure 𝒰 M j)).left =
        ((Over.pullback ψ).map (gluingOverlapSecond 𝒰 M i j)).left
AlgebraicGeometry.Scheme.Cover.recoveredPullbackOverlapTransfer_chartMap
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackOverlapTransfer_chartMap (i j : 𝒰.I₀) :
    recoveredPullbackOverlapTransfer ψ 𝒰 M Z e i j ≫ recoveredPullbackChartMap ψ 𝒰 M Z e j =
      ((Over.pullback ψ).map (gluingOverlapFirst 𝒰 M i j)).left ≫
        recoveredPullbackChartMap ψ 𝒰 M Z e i
AlgebraicGeometry.Scheme.Cover.recoveredPullbackTransition

The transition map between the two orders of a recovered overlap.

Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
def recoveredPullbackTransition (i j : 𝒰.I₀) :
    (Over.pullback ψ).obj (gluingOverlapOver 𝒰 M (i, j)) ⟶
      (Over.pullback ψ).obj (gluingOverlapOver 𝒰 M (j, i))
AlgebraicGeometry.Scheme.Cover.recoveredPullbackTransition_first
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackTransition_first (i j : 𝒰.I₀) :
    (recoveredPullbackTransition ψ 𝒰 M Z e i j).left ≫
      ((Over.pullback ψ).map (gluingOverlapFirst 𝒰 M j i)).left =
      recoveredPullbackOverlapTransfer ψ 𝒰 M Z e i j
AlgebraicGeometry.Scheme.Cover.recoveredPullbackTransition_chartMap
Source context 8 commands

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

noncomputable section
open CategoryTheory Limits AlgebraicGeometry
universe u
namespace AlgebraicGeometry.Scheme.Cover
variable {X Y : Scheme.{u}} (ψ : Y ⟶ X) (𝒰 : X.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over Y)
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.fst (𝒰.f i) ψ)).obj (M i) ≅
    (Over.pullback (pullback.snd (𝒰.f i) ψ)).obj Z)
theorem recoveredPullbackTransition_chartMap (i j : 𝒰.I₀) :
    (recoveredPullbackTransition ψ 𝒰 M Z e i j).left ≫
      ((Over.pullback ψ).map (gluingOverlapFirst 𝒰 M j i)).left ≫
        recoveredPullbackChartMap ψ 𝒰 M Z e j =
      ((Over.pullback ψ).map (gluingOverlapFirst 𝒰 M i j)).left ≫
        recoveredPullbackChartMap ψ 𝒰 M Z e i