Module

DVFHomExt.lean

Nyll.ValuedFieldTheory.Valuation.Completion.DVFHomExt
1 declaration indexed from sourceView source ↗

Homomorphisms out of finite extension completions

The actual tensor map onto an extension completion makes a homomorphism over the base completion determined by its values on the original field.

Declarations

ValuationTheory.DiscreteValuationField.DVF.completionAlgHom_ext

Homomorphisms from a finite extension completion over the base completion are equal if they agree on the original extension field.

Source context 2 commands

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

namespace ValuationTheory.DiscreteValuationField.DVF
variable {K L : Type*} [Field K] [Field L] [Algebra K L]
  (base : DVF K) (target : DVF L)
  [hExtension : base.valuation.HasExtension target.valuation]
theorem completionAlgHom_ext [FiniteDimensional K L]
    {B : Type*} [CommRing B] [Algebra base.valuation.Completion B]
    (f g : @AlgHom base.valuation.Completion target.valuation.Completion B _ _ _
      (completionAlgebra base target) _)
    (h : ∀ l : L, f (l : target.valuation.Completion) = g (l : target.valuation.Completion)) :
    f = g