Module

Teichmuller.lean

Nyll.ValuedFieldTheory.LocalField.Padic.Teichmuller
7 declarations indexed from sourceView source ↗

Teichmüller representatives in the p-adic units

Hensel lifting in the concrete complete discrete valuation field ℚ_[p] gives a multiplicative section of reduction to (ZMod p)ˣ. Its values are (p - 1)-st roots of unity, including when p = 2.

Declarations

LocalFieldTheory.DiscreteValuationField.Examples.Qp.teichmullerIntegerEquiv
Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
def teichmullerIntegerEquiv : ℤ_[p] ≃+* (padicCompleteDVF p).valuationSubring
LocalFieldTheory.DiscreteValuationField.Examples.Qp.teichmullerResidueEquiv
Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
def teichmullerResidueEquiv : (padicCompleteDVF p).residueField ≃+* ZMod p
LocalFieldTheory.DiscreteValuationField.Examples.Qp.toZMod_valuationSubring_symm
Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
theorem toZMod_valuationSubring_symm
    (x : (padicCompleteDVF p).valuationSubring) :
    PadicInt.toZMod ((teichmullerIntegerEquiv p).symm x) =
      teichmullerResidueEquiv p ((padicCompleteDVF p).residueMap x)
LocalFieldTheory.DiscreteValuationField.Examples.Qp.teichmullerRoots
Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
def teichmullerRoots :
    (ZMod p)ˣ →* residueRootsOfUnityGroup (padicCompleteDVF p)
LocalFieldTheory.DiscreteValuationField.Examples.Qp.teichmullerUnits

The multiplicative Teichmüller section from residue units to p-adic units.

Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
def teichmullerUnits : (ZMod p)ˣ →* ℤ_[p]ˣ
LocalFieldTheory.DiscreteValuationField.Examples.Qp.toZMod_teichmullerUnits

Reducing a Teichmüller representative recovers the original residue unit.

Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
theorem toZMod_teichmullerUnits (u : (ZMod p)ˣ) :
    Units.map PadicInt.toZMod.toMonoidHom (teichmullerUnits p u) = u
LocalFieldTheory.DiscreteValuationField.Examples.Qp.teichmullerUnits_pow

Every Teichmüller representative is a (p - 1)-st root of unity.

Source context 5 commands

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

noncomputable section
namespace LocalFieldTheory.DiscreteValuationField.Examples.Qp
open CompleteDVF.higherPrincipalUnitGroup
variable (p : ℕ) [Fact p.Prime]

-- The only additional instance is the existing finiteness proof for Qp's residue field.
attribute [local instance] padicCompleteDVF_residueField_finite
theorem teichmullerUnits_pow (u : (ZMod p)ˣ) :
    teichmullerUnits p u ^ (p - 1) = 1