English
In a separable setting, the q^n-th power map on a basis gives another basis with the same span.
Русский
В разделяемом случае отображение по q^n на базис дает другой базис той же линейной оболочки.
LaTeX
$$$\text{new basis spans same space as old}$$$
Lean4
/-- The same-universe version of `Field.lift_rank_mul_lift_sepDegree_of_isSeparable`. -/
theorem rank_mul_sepDegree_of_isSeparable (K : Type v) [Field K] [Algebra F K] [Algebra E K] [IsScalarTower F E K]
[Algebra.IsSeparable F E] : Module.rank F E * sepDegree E K = sepDegree F K := by
simpa only [Cardinal.lift_id] using lift_rank_mul_lift_sepDegree_of_isSeparable F E K