Module

OrdinaryHenselizationComparison.lean

Nyll.EtaleFundamentalGroups.StrictHenselian.OrdinaryHenselizationComparison
4 declarations indexed from sourceView source ↗

The actual ordinary-to-pointed-stalk comparison

The ordinary universal lift gives the map into the existing pointed étale stalk. Uniqueness proves the literal triangle with its existing Henselian target map. This also applies to the original strict stalk inside a normalization-prime localization.

Declarations

EtaleFundamentalGroups.StrictHenselian.ordinaryHenselizationToGeometricStalk

The actual ordinary universal lift into the existing pointed étale stalk.

Source context 6 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory
namespace EtaleFundamentalGroups.StrictHenselian
universe u
section Point
variable {A Ω : Type u} [CommRing A] [IsLocalRing A] [Field Ω]
  (φ : A →+* Ω) [IsLocalHom φ]
def ordinaryHenselizationToGeometricStalk :
    ordinaryHenselization A →+* geometricStalk (Spec.map (CommRingCat.ofHom φ))
EtaleFundamentalGroups.StrictHenselian.ordinaryHenselizationToGeometricStalk_isLocalHom
Source context 6 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory
namespace EtaleFundamentalGroups.StrictHenselian
universe u
section Point
variable {A Ω : Type u} [CommRing A] [IsLocalRing A] [Field Ω]
  (φ : A →+* Ω) [IsLocalHom φ]
instance ordinaryHenselizationToGeometricStalk_isLocalHom :
    IsLocalHom (ordinaryHenselizationToGeometricStalk φ)
EtaleFundamentalGroups.StrictHenselian.ordinaryHenselizationToGeometricStalk_comp_map

The comparison preserves the original map from the base ring.

Source context 6 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory
namespace EtaleFundamentalGroups.StrictHenselian
universe u
section Point
variable {A Ω : Type u} [CommRing A] [IsLocalRing A] [Field Ω]
  (φ : A →+* Ω) [IsLocalHom φ]
theorem ordinaryHenselizationToGeometricStalk_comp_map :
    (ordinaryHenselizationToGeometricStalk φ).comp (ordinaryHenselizationMap A) =
      geometricStalkStructureMap φ
EtaleFundamentalGroups.StrictHenselian.ordinaryHenselizationToGeometricStalk_comp_toHenselian

The ordinary-to-pointed comparison and the existing actual Henselian target map compose to the original ordinary universal lift.

Source context 5 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory
namespace EtaleFundamentalGroups.StrictHenselian
universe u
variable {A S : Type u} [CommRing A] [IsLocalRing A]
  [CommRing S] [HenselianLocalRing S] (f : A →+* S) [IsLocalHom f]
theorem ordinaryHenselizationToGeometricStalk_comp_toHenselian :
    (geometricStalkToHenselian f).comp
        (ordinaryHenselizationToGeometricStalk ((IsLocalRing.residue S).comp f)) =
      ordinaryHenselizationLift f