Module

ActualFiniteTameIndex.lean

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

Finite tame degrees as roots-system indices

Proves positivity and base-ring invertibility of the finite tame degree, and uses them to construct an index of the canonical roots system.

Declarations

EtaleFundamentalGroups.Inertia.actualFiniteStageTameOrder_pos

Positivity of the degree at the original chosen prime.

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)
  [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)) [Q.IsMaximal]
theorem actualFiniteStageTameOrder_pos (E : FiniteGaloisIntermediateField K L) :
    0 < actualFiniteStageTameOrder A K L Q E
EtaleFundamentalGroups.Inertia.actualFiniteStageTameOrder_isUnit

Invertibility of that actual degree in the original DVR.

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)
  [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)) [Q.IsMaximal]
theorem actualFiniteStageTameOrder_isUnit (E : FiniteGaloisIntermediateField K L) :
    IsUnit (actualFiniteStageTameOrder A K L Q E : A)
EtaleFundamentalGroups.Inertia.actualFiniteStageTameIndex

The actual finite tame degree as an index of the canonical base-residue roots system. Its invertibility has been proved from the original data.

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)
  [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)) [Q.IsMaximal]
def actualFiniteStageTameIndex (E : FiniteGaloisIntermediateField K L) :
    InvertibleExponent (IsLocalRing.ResidueField A)