Module

ActualFiniteTameCoordinateKernel.lean

Nyll.EtaleFundamentalGroups.Inertia.ActualFiniteTameCoordinateKernel
2 declarations indexed from sourceView source ↗

Kernels of the actual finite coordinates on original inertia

The ambient residue-field embedding is injective. Composing it with the SAME normalized finite character therefore leaves the actual wild kernel unchanged, before pulling it back through original inertia restriction.

Declarations

EtaleFundamentalGroups.Inertia.actualFiniteRootsGroupMap_injective

The actual coefficient embedding is injective on its actual roots group.

Source context 4 commands

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

namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
variable (A : Type u) (K : Type v) (L : Type w)
  [CommRing A] [IsDomain A] [IsDiscreteValuationRing A]
  [Field K] [Field L] [Algebra A K] [IsFractionRing A K]
  [Algebra K L] [Algebra A L] [IsScalarTower A K L] [IsGalois K L]
  (Q : Ideal (normalizationCommAlgCat A L).carrier) [Q.IsMaximal]
theorem actualFiniteRootsGroupMap_injective (E : FiniteGaloisIntermediateField K L) :
    Function.Injective (actualFiniteRootsGroupMap A K L Q E).hom'.toFun
EtaleFundamentalGroups.Inertia.actualFiniteTameCoordinate_ker

The actual coordinate has the pullback of the independent finite wild subgroup as its kernel.

Source context 4 commands

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

namespace EtaleFundamentalGroups.Inertia
open SchemeTheory
universe u v w
variable (A : Type u) (K : Type v) (L : Type w)
  [CommRing A] [IsDomain A] [IsDiscreteValuationRing A]
  [Field K] [Field L] [Algebra A K] [IsFractionRing A K]
  [Algebra K L] [Algebra A L] [IsScalarTower A K L] [IsGalois K L]
  (Q : Ideal (normalizationCommAlgCat A L).carrier) [Q.IsMaximal]
theorem actualFiniteTameCoordinate_ker (E : FiniteGaloisIntermediateField K L) :
    (actualFiniteTameCoordinate A K L Q E).hom'.ker =
      (actualFiniteWildSubgroup A K L Q E).comap
        (actualFiniteInertiaRestriction A K L Q E).hom'