Module

WithValScalars.lean

Nyll.ValuedFieldTheory.Valuation.Completion.WithValScalars
3 declarations indexed from sourceView source ↗

Ground-field scalars on a valued completion

Scalar multiplication on WithVal v is multiplication by the image of the scalar. Its uniform continuity supplies the existing completion algebra over the original field, without choosing a topology on that field.

Declarations

WithVal.uniformContinuousConstSMul

The canonical ground-field action on WithVal v is uniformly continuous in its second argument.

Source context 2 commands

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

namespace WithVal
variable {K Γ : Type*} [Ring K] [LinearOrderedCommGroupWithZero Γ]
instance uniformContinuousConstSMul (v : Valuation K Γ) :
    UniformContinuousConstSMul K (WithVal v) where
  uniformContinuous_const_smul k := by
    change UniformContinuous (fun x : WithVal v => toVal v k * x)
    exact uniformContinuous_mul_left' _
WithVal.uniformContinuousConstSMul_algebra

Scalars from a specified algebra act uniformly continuously on its valued model. This theorem does not register another global scalar instance.

Source context 2 commands

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

namespace WithVal
variable {K Γ : Type*} [Ring K] [LinearOrderedCommGroupWithZero Γ]
theorem uniformContinuousConstSMul_algebra {R : Type*} [CommSemiring R]
    [Algebra R K] (v : Valuation K Γ) :
    UniformContinuousConstSMul R (WithVal v) where
  uniformContinuous_const_smul r := by
    have heq : (fun x : WithVal v => r • x) =
        (fun x => WithVal.toVal v (algebraMap R K r) * x) := by
      funext x
      apply WithVal.ofVal_injective v
      exact Algebra.smul_def r x.ofVal
    rw [heq]
    exact uniformContinuous_mul_left' _
WithVal.denseRange_algebraMap_completion

The canonical map from the original ring to its valuation completion has dense range, without choosing a topology on the original ring.

Source context 2 commands

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

namespace WithVal
variable {K Γ : Type*} [Ring K] [LinearOrderedCommGroupWithZero Γ]
theorem denseRange_algebraMap_completion {R : Type*} [CommRing R] (v : Valuation R Γ) :
    DenseRange (algebraMap R v.Completion)