Module

Completeness.lean

Nyll.ValuedFieldTheory.Valuation.AbsoluteValue.Completeness
8 declarations indexed from sourceView source ↗

Minimal absolute-value norm API

This file keeps only the lightweight explicit definitions used by the current Section 4 formalization. The old experimental completion and norm formula development was removed because it duplicated mathlib APIs and no longer compiled.

Declarations

AlgebraicNumberTheory.Valuations.IsCompleteForAbsoluteValue

A valued field is complete if it is complete for the uniformity induced by its absolute value.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
def IsCompleteForAbsoluteValue {K : Type*} [Field K] (v : AbsoluteValue K ℝ) : Prop
AlgebraicNumberTheory.Valuations.absoluteValue_uniformSpace_eq_toNormedField

The uniformity attached directly to an absolute value agrees with the uniformity coming from the normed-field structure induced by that absolute value.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
theorem absoluteValue_uniformSpace_eq_toNormedField
    {K : Type*} [Field K] (v : AbsoluteValue K ℝ) :
    v.uniformSpace = (AbsoluteValue.toNormedField v).toUniformSpace
AlgebraicNumberTheory.Valuations.absoluteValueCompleteness_completeSpace_withAbs_iff_complete

Completeness in the absolute-value uniformity is the same as completeness of the corresponding WithAbs normed field.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
theorem absoluteValueCompleteness_completeSpace_withAbs_iff_complete
    {K : Type*} [Field K] (v : AbsoluteValue K ℝ) :
    CompleteSpace (WithAbs v) ↔ IsCompleteForAbsoluteValue v
AlgebraicNumberTheory.Valuations.completeSpace_withAbs_of_isCompleteForAbsoluteValue

A complete valued field is complete as the corresponding WithAbs normed field.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
theorem completeSpace_withAbs_of_isCompleteForAbsoluteValue
    {K : Type*} [Field K] (v : AbsoluteValue K ℝ)
    (hcomplete : IsCompleteForAbsoluteValue v) :
    CompleteSpace (WithAbs v)
AlgebraicNumberTheory.Valuations.absoluteValueCompleteness_complete_iff_cauchySeq_converges

Sequence form of the sequential completeness criterion: a complete valued field is exactly one where every Cauchy sequence in the absolute-value topology converges.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
theorem absoluteValueCompleteness_complete_iff_cauchySeq_converges
    {K : Type*} [Field K] (v : AbsoluteValue K ℝ) :
    IsCompleteForAbsoluteValue v ↔
      ∀ u : ℕ → WithAbs v, CauchySeq u →
        ∃ a : WithAbs v, Filter.Tendsto u Filter.atTop (nhds a)
AlgebraicNumberTheory.Valuations.withAbsNontriviallyNormedField

The nontrivial-valuation convention excludes the trivial valuation; this supplies the corresponding mathlib NontriviallyNormedField instance for WithAbs v.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
def withAbsNontriviallyNormedField
    {K : Type*} [Field K] (v : AbsoluteValue K ℝ) (hv : v.IsNontrivial) :
    NontriviallyNormedField (WithAbs v)
AlgebraicNumberTheory.Valuations.finiteExtensionNormFormulaValue

The finite-degree norm-formula candidate: x ↦ |N_{L/K}(x)|^{1/[L:K]}.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
def finiteExtensionNormFormulaValue
    {K L : Type*} [Field K] [Field L] [Algebra K L] [FiniteDimensional K L]
    (v : AbsoluteValue K ℝ) (x : L) : ℝ
AlgebraicNumberTheory.Valuations.finiteExtensionNormFormulaValue_nonneg

The finite-degree norm formula candidate is nonnegative.

Source context 3 commands

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

noncomputable section
namespace AlgebraicNumberTheory
namespace Valuations
theorem finiteExtensionNormFormulaValue_nonneg
    {K L : Type*} [Field K] [Field L] [Algebra K L] [FiniteDimensional K L]
    (v : AbsoluteValue K ℝ) (x : L) :
    0 ≤ finiteExtensionNormFormulaValue v x