Module

SeparableGaloisMap.lean

Nyll.GaloisCohomology.Topology.SeparableGaloisMap
4 declarations indexed from sourceView source ↗

Restriction maps on the separable parts of algebraic closures

The algebraic-closure embedding used for absolute Galois restriction preserves the separable closure. Its restriction intertwines the actual Galois maps.

Declarations

Field.absoluteGaloisGroup.separableClosureLift

The chosen algebraic-closure embedding restricts to the separable closures.

Source context 2 commands

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

namespace Field.absoluteGaloisGroup
variable {K L : Type*} [Field K] [Field L]
def separableClosureLift (f : K →+* L) :
    SeparableClosure K →+* SeparableClosure L
Field.absoluteGaloisGroup.separableClosureLift_coe

Inclusion into the algebraic closure recovers the chosen closure embedding.

Source context 2 commands

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

namespace Field.absoluteGaloisGroup
variable {K L : Type*} [Field K] [Field L]
theorem separableClosureLift_coe (f : K →+* L) (s : SeparableClosure K) :
    (separableClosureLift f s : AlgebraicClosure L) = closureLift f (s : AlgebraicClosure K)
Field.absoluteGaloisGroup.separableClosureLift_algebraMap

The separable-closure embedding extends the original field embedding.

Source context 2 commands

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

namespace Field.absoluteGaloisGroup
variable {K L : Type*} [Field K] [Field L]
theorem separableClosureLift_algebraMap (f : K →+* L) (x : K) :
    separableClosureLift f (algebraMap K (SeparableClosure K) x) =
      algebraMap L (SeparableClosure L) (f x)
Field.absoluteGaloisGroup.map_separableClosureLift

Galois restriction intertwines the induced embedding of separable closures.

Source context 2 commands

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

namespace Field.absoluteGaloisGroup
variable {K L : Type*} [Field K] [Field L]
theorem map_separableClosureLift (f : K →+* L)
    (σ : Gal(AlgebraicClosure L/L)) (s : SeparableClosure K) :
    separableClosureLift f
        (ValuationTheory.Completion.separableClosureAutEquiv K (map f σ) s) =
      ValuationTheory.Completion.separableClosureAutEquiv L σ (separableClosureLift f s)