Module

ActualFiniteWildImage.lean

Nyll.EtaleFundamentalGroups.Inertia.ActualFiniteWildImage
3 declarations indexed from sourceView source ↗

Actual finite wild subgroup images

Actual intrinsic finite inertia restriction is onto. The SAME actual wild subgroups have proved primary cardinalities, prime-to-characteristic indices and target normality. The original field environment is closed before the finite-group Sylow image theorem is applied.

Declarations

EtaleFundamentalGroups.Inertia.actualFiniteWildSubgroup_map_of_baseResidue_charP

Actual intrinsic inertia restriction has exactly the actual wild image in positive residue characteristic.

Source context 5 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
variable (A : Type u) (K : Type v) (L : Type w)
  [rA : CommRing A] [dA : IsDomain A] [vA : IsDiscreteValuationRing A]
  [fK : Field K] [fL : Field L] [aAK : Algebra A K] [frAK : IsFractionRing A K]
  [aKL : Algebra K L] [aAL : Algebra A L] [tAKL : IsScalarTower A K L] [gKL : IsGalois K L]
  (Q : Ideal (normalizationCommAlgCat A L).carrier) [qMax : Q.IsMaximal]
  (E F : FiniteGaloisIntermediateField K L) (hEF : E ≤ F)
theorem actualFiniteWildSubgroup_map_of_baseResidue_charP
    (p : ℕ) [hp : Fact p.Prime] [charA : CharP (IsLocalRing.ResidueField A) p] :
    (actualFiniteWildSubgroup A K L Q F).map
        (actualFiniteInertiaTowerRestriction A K L Q E F hEF).hom' =
      actualFiniteWildSubgroup A K L Q E
EtaleFundamentalGroups.Inertia.actualFiniteWildSubgroup_map_of_baseResidue_charZero

In residue characteristic zero both actual wild subgroups are trivial, so the same inertia restriction has exactly the actual wild image.

Source context 5 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
variable (A : Type u) (K : Type v) (L : Type w)
  [rA : CommRing A] [dA : IsDomain A] [vA : IsDiscreteValuationRing A]
  [fK : Field K] [fL : Field L] [aAK : Algebra A K] [frAK : IsFractionRing A K]
  [aKL : Algebra K L] [aAL : Algebra A L] [tAKL : IsScalarTower A K L] [gKL : IsGalois K L]
  (Q : Ideal (normalizationCommAlgCat A L).carrier) [qMax : Q.IsMaximal]
  (E F : FiniteGaloisIntermediateField K L) (hEF : E ≤ F)
theorem actualFiniteWildSubgroup_map_of_baseResidue_charZero
    [CharZero (IsLocalRing.ResidueField A)] :
    (actualFiniteWildSubgroup A K L Q F).map
        (actualFiniteInertiaTowerRestriction A K L Q E F hEF).hom' =
      actualFiniteWildSubgroup A K L Q E
EtaleFundamentalGroups.Inertia.actualFiniteWildSubgroup_map

Actual finite inertia restriction maps the SAME intrinsic wild subgroup onto the target wild subgroup in every residue characteristic.

Source context 5 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
variable (A : Type u) (K : Type v) (L : Type w)
  [rA : CommRing A] [dA : IsDomain A] [vA : IsDiscreteValuationRing A]
  [fK : Field K] [fL : Field L] [aAK : Algebra A K] [frAK : IsFractionRing A K]
  [aKL : Algebra K L] [aAL : Algebra A L] [tAKL : IsScalarTower A K L] [gKL : IsGalois K L]
  (Q : Ideal (normalizationCommAlgCat A L).carrier) [qMax : Q.IsMaximal]
  (E F : FiniteGaloisIntermediateField K L) (hEF : E ≤ F)
theorem actualFiniteWildSubgroup_map :
    (actualFiniteWildSubgroup A K L Q F).map
        (actualFiniteInertiaTowerRestriction A K L Q E F hEF).hom' =
      actualFiniteWildSubgroup A K L Q E