AlgebraicCurves.FunctionFields.Proofs.Exists_separating_transcendental_of_perfectField.AlgebraicCurve.SeparatingTranscendentalOfPerfectField.isTranscendenceBasis_of_transcendental
Source context 6 commands
Surrounding namespaces, section variables, and local commands at this declaration.
section ProofImplementation
namespace AlgebraicCurves.FunctionFields.Proofs.Exists_separating_transcendental_of_perfectField
open IntermediateField
namespace AlgebraicCurve
namespace SeparatingTranscendentalOfPerfectField
variable {K F : Type*} [Field K] [Field F] [Algebra K F]Lean source · full declaration
theorem isTranscendenceBasis_of_transcendental {x : F} (hx : Transcendental K x)
(hfd : FiniteDimensional K⟮x⟯ F) : IsTranscendenceBasis K (fun _ : Fin 1 => x) := by
have hind : AlgebraicIndependent K (fun _ : Fin 1 => x) :=
algebraicIndependent_unique_type_iff.mpr hx
refine hind.isTranscendenceBasis_iff_isAlgebraic.mpr ?_
have hr : Set.range (fun _ : Fin 1 => x) = ({x} : Set F) := by
ext y
simp [eq_comm]
rw [hr, ← IntermediateField.isAlgebraic_adjoin_iff_top]
have := hfd
exact Algebra.IsAlgebraic.of_finite K⟮x⟯ F