Module

HenselianSeparableTensorField.lean

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

Separable algebraic extensions after Henselian completion

Each tensor element comes from a finite subextension. Inverting a nonzero lift there and mapping the inverse back proves the field property without assuming a comparison map is injective.

Declarations

ValuationTheory.DiscreteValuationField.HenselianDVF.completionTensor_isField_of_isSeparable

Completing a Henselian DVF preserves the field property of scalar extension by any separable algebraic extension, including a separable closure.

Source context 3 commands

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

namespace ValuationTheory.DiscreteValuationField.HenselianDVF
open scoped TensorProduct
variable {K : Type*} [Field K]
theorem completionTensor_isField_of_isSeparable (base : HenselianDVF K)
    (L : Type*) [Field L] [Algebra K L] [Algebra.IsSeparable K L] :
    IsField (base.valuation.Completion ⊗[K] L)