Module

CoefficientEquation.lean

Nyll.ClassFieldTheory.LubinTate.FormalModule.CoefficientEquation
6 declarations indexed from sourceView source ↗

Coefficient equations for a fixed uniformizer

For a positive degree, the scalar factor 1 - π ^ r is a unit whenever π is a uniformizer. Consequently the corresponding scalar coefficient equation has a unique solution in the valuation ring.

Declarations

LubinTate.SameUniformizer.residueMap_uniformizer_eq_zero

A chosen uniformizer reduces to zero in the residue field.

Source context 7 commands

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

noncomputable section
universe u v
namespace LubinTate
namespace SameUniformizer
open LocalFieldTheory.DiscreteValuationField
variable {K : Type u} [Field K]
variable {F : LocalField.{u, v} K} {π : F.valuationSubring}
theorem residueMap_uniformizer_eq_zero
    (hπ : F.toCompleteDVF.valuation.IsUniformizer (π : K)) :
    F.residueMap π = 0
LubinTate.SameUniformizer.uniformizer_dvd_of_residueMap_eq_zero

An element reducing to zero is divisible by the chosen uniformizer.

Source context 7 commands

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

noncomputable section
universe u v
namespace LubinTate
namespace SameUniformizer
open LocalFieldTheory.DiscreteValuationField
variable {K : Type u} [Field K]
variable {F : LocalField.{u, v} K} {π : F.valuationSubring}
theorem uniformizer_dvd_of_residueMap_eq_zero
    (hπ : F.toCompleteDVF.valuation.IsUniformizer (π : K))
    {a : F.valuationSubring} (ha : F.residueMap a = 0) :
    π ∣ a
LubinTate.SameUniformizer.residueMap_uniformizer_pow_eq_zero

Every positive power of a uniformizer reduces to zero.

Source context 7 commands

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

noncomputable section
universe u v
namespace LubinTate
namespace SameUniformizer
open LocalFieldTheory.DiscreteValuationField
variable {K : Type u} [Field K]
variable {F : LocalField.{u, v} K} {π : F.valuationSubring}
theorem residueMap_uniformizer_pow_eq_zero
    (hπ : F.toCompleteDVF.valuation.IsUniformizer (π : K))
    {r : ℕ} (hr : r ≠ 0) :
    F.residueMap (π ^ r) = 0
LubinTate.SameUniformizer.isUnit_one_sub_uniformizer_pow

For positive r, the factor 1 - pi ^ r is a unit of O_K.

Source context 7 commands

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

noncomputable section
universe u v
namespace LubinTate
namespace SameUniformizer
open LocalFieldTheory.DiscreteValuationField
variable {K : Type u} [Field K]
variable {F : LocalField.{u, v} K} {π : F.valuationSubring}
theorem isUnit_one_sub_uniformizer_pow
    (hπ : F.toCompleteDVF.valuation.IsUniformizer (π : K))
    {r : ℕ} (hr : r ≠ 0) :
    IsUnit (1 - π ^ r)
LubinTate.SameUniformizer.existsUnique_mul_eq_of_isUnit

Left multiplication by a unit has a unique preimage for every right-hand side.

Source context 7 commands

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

noncomputable section
universe u v
namespace LubinTate
namespace SameUniformizer
open LocalFieldTheory.DiscreteValuationField
variable {K : Type u} [Field K]
variable {F : LocalField.{u, v} K} {π : F.valuationSubring}
theorem existsUnique_mul_eq_of_isUnit
    {R : Type*} [CommRing R] {a : R} (ha : IsUnit a) (b : R) :
    ∃! x : R, a * x = b
LubinTate.SameUniformizer.existsUnique_one_sub_uniformizer_pow_mul_eq

The scalar coefficient equation in positive total degree has a unique solution in the valuation ring.

Source context 7 commands

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

noncomputable section
universe u v
namespace LubinTate
namespace SameUniformizer
open LocalFieldTheory.DiscreteValuationField
variable {K : Type u} [Field K]
variable {F : LocalField.{u, v} K} {π : F.valuationSubring}
theorem existsUnique_one_sub_uniformizer_pow_mul_eq
    (hπ : F.toCompleteDVF.valuation.IsUniformizer (π : K))
    {r : ℕ} (hr : r ≠ 0) (b : F.valuationSubring) :
    ∃! x : F.valuationSubring, (1 - π ^ r) * x = b