Module

CoefficientFrobenius.lean

Nyll.ClassFieldTheory.LubinTate.EqualCharacteristic.Frobenius.CoefficientFrobenius
5 declarations indexed from sourceView source ↗

The equal-characteristic completed-unramified construction: equal-characteristic Frobenius on

the completed unramified ring

For a finite field k, arithmetic Frobenius acts on AlgebraicClosure k by the #k-power map and hence coefficientwise on (AlgebraicClosure k)[[T]]. These definitions belong to the completed maximal-unramified source used in the equal-characteristic completed-unramified construction; the theta construction of the equal-characteristic theta construction depends on them, not conversely.

This is an equal-characteristic specialization of the general local-field construction, not a claim that Lemma the equal-characteristic completed-unramified construction is complete in general.

Declarations

LubinTate.EqualCharacteristic.equalCharacteristicCoefficientFrobenius

Arithmetic Frobenius on the algebraic closure of the finite coefficient field.

Source context 6 commands

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

noncomputable section
open scoped PowerSeries
universe u
namespace LubinTate
namespace EqualCharacteristic
variable (k : Type u) [Field k] [Finite k]
def equalCharacteristicCoefficientFrobenius :
    AlgebraicClosure k ≃ₐ[k] AlgebraicClosure k
LubinTate.EqualCharacteristic.equalCharacteristicCoefficientFrobenius_apply

States the theorem equalCharacteristicCoefficientFrobenius_apply.

Source context 6 commands

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

noncomputable section
open scoped PowerSeries
universe u
namespace LubinTate
namespace EqualCharacteristic
variable (k : Type u) [Field k] [Finite k]
theorem equalCharacteristicCoefficientFrobenius_apply
    (x : AlgebraicClosure k) :
    equalCharacteristicCoefficientFrobenius k x = x ^ Nat.card k
LubinTate.EqualCharacteristic.equalCharacteristicPowerSeriesFrobenius

Arithmetic Frobenius on the completed maximal-unramified coefficient ring, acting coefficientwise and fixing T.

Source context 6 commands

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

noncomputable section
open scoped PowerSeries
universe u
namespace LubinTate
namespace EqualCharacteristic
variable (k : Type u) [Field k] [Finite k]
def equalCharacteristicPowerSeriesFrobenius :
    (AlgebraicClosure k)⟦X⟧ →+* (AlgebraicClosure k)⟦X⟧
LubinTate.EqualCharacteristic.equalCharacteristicPowerSeriesFrobenius_coeff

States the theorem equalCharacteristicPowerSeriesFrobenius_coeff.

Source context 6 commands

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

noncomputable section
open scoped PowerSeries
universe u
namespace LubinTate
namespace EqualCharacteristic
variable (k : Type u) [Field k] [Finite k]
theorem equalCharacteristicPowerSeriesFrobenius_coeff
    (f : (AlgebraicClosure k)⟦X⟧) (n : ℕ) :
    PowerSeries.coeff n (equalCharacteristicPowerSeriesFrobenius k f) =
      (PowerSeries.coeff n f) ^ Nat.card k
LubinTate.EqualCharacteristic.equalCharacteristicPowerSeriesFrobenius_X

States the theorem equalCharacteristicPowerSeriesFrobenius_X.

Source context 6 commands

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

noncomputable section
open scoped PowerSeries
universe u
namespace LubinTate
namespace EqualCharacteristic
variable (k : Type u) [Field k] [Finite k]
theorem equalCharacteristicPowerSeriesFrobenius_X :
    equalCharacteristicPowerSeriesFrobenius k
        (PowerSeries.X : (AlgebraicClosure k)⟦X⟧) =
      PowerSeries.X