Module

RecoveredCoefficientRecovery.lean

Nyll.EtaleFundamentalGroups.FiniteEtale.FiniteField.RecoveredCoefficientRecovery
2 declarations indexed from sourceView source ↗

Recovered Coefficient Recovery

The recovered literal coefficient charts form an actual cover of the input scheme.

Declarations

EtaleFundamentalGroups.recoveredCoefficientChartCover

The recovered literal coefficient charts form an actual cover of the input scheme.

Source context 13 commands

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

noncomputable section
universe u
open CategoryTheory Limits AlgebraicGeometry
namespace EtaleFundamentalGroups
variable (k L : Type u) [Field k] [Field L] [Algebra k L]
variable (S : Scheme.{u}) (f : S ⟶ Spec (CommRingCat.of k)) (𝒰 : S.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over (pullback (Spec.map (CommRingCat.ofHom (algebraMap k L))) f))
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.snd (Spec.map (CommRingCat.ofHom (algebraMap k L)))
    (𝒰.f i ≫ f))).obj (M i) ≅
      (Over.pullback ((constantFieldOpenCover k L S f 𝒰).f i)).obj Z)
local notation "φ" => Spec.map (CommRingCat.ofHom (algebraMap k L))
local notation "𝒰L" => constantFieldOpenCover k L S f 𝒰
local notation "ML" => (fun i : 𝒰.I₀ ↦
  Functor.obj (Over.pullback (pullback.snd φ (𝒰.f i ≫ f))) (M i))
local notation "D" => Scheme.Cover.recoveredOverlapGlueData 𝒰L Z ML e
def recoveredCoefficientChartCover : Z.left.OpenCover
EtaleFundamentalGroups.recoveredCoefficientTransition_isPullback

The literal coefficient overlap is the actual intersection of the two recovered literal charts in the input scheme.

Source context 13 commands

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

noncomputable section
universe u
open CategoryTheory Limits AlgebraicGeometry
namespace EtaleFundamentalGroups
variable (k L : Type u) [Field k] [Field L] [Algebra k L]
variable (S : Scheme.{u}) (f : S ⟶ Spec (CommRingCat.of k)) (𝒰 : S.OpenCover)
variable (M : ∀ i : 𝒰.I₀, Over (𝒰.X i))
variable (Z : Over (pullback (Spec.map (CommRingCat.ofHom (algebraMap k L))) f))
variable (e : ∀ i : 𝒰.I₀,
  (Over.pullback (pullback.snd (Spec.map (CommRingCat.ofHom (algebraMap k L)))
    (𝒰.f i ≫ f))).obj (M i) ≅
      (Over.pullback ((constantFieldOpenCover k L S f 𝒰).f i)).obj Z)
local notation "φ" => Spec.map (CommRingCat.ofHom (algebraMap k L))
local notation "𝒰L" => constantFieldOpenCover k L S f 𝒰
local notation "ML" => (fun i : 𝒰.I₀ ↦
  Functor.obj (Over.pullback (pullback.snd φ (𝒰.f i ≫ f))) (M i))
local notation "D" => Scheme.Cover.recoveredOverlapGlueData 𝒰L Z ML e
theorem recoveredCoefficientTransition_isPullback (i j : 𝒰.I₀) :
    IsPullback (coefficientOverlapFirstMap φ f (𝒰.f i) (𝒰.f j) (M i).hom)
      (recoveredCoefficientTransition k L S f 𝒰 M Z e i j ≫
        coefficientOverlapFirstMap φ f (𝒰.f j) (𝒰.f i) (M j).hom)
      (recoveredCoefficientChartMap k L S f 𝒰 M Z e i)
      (recoveredCoefficientChartMap k L S f 𝒰 M Z e j)