English
The same-universe version of the tower rule for separable degrees under algebraicity: lift(sepDegree F E) · lift(sepDegree E K) = lift(sepDegree F K).
Русский
Тот же закон башни для сепарабельных степеней в рамках алгебраичности: lift(sepDegree F E) · lift(sepDegree E K) = lift(sepDegree F K).
LaTeX
$$Cardinal.lift(sepDegree F E) · Cardinal.lift(sepDegree E K) = Cardinal.lift(sepDegree F K)$$
Lean4
/-- The same-universe version of `Field.lift_sepDegree_mul_lift_sepDegree_of_isAlgebraic`. -/
@[stacks 09HK "Part 1"]
theorem sepDegree_mul_sepDegree_of_isAlgebraic (K : Type v) [Field K] [Algebra F K] [Algebra E K] [IsScalarTower F E K]
[Algebra.IsAlgebraic F E] : sepDegree F E * sepDegree E K = sepDegree F K := by
simpa only [Cardinal.lift_id] using lift_sepDegree_mul_lift_sepDegree_of_isAlgebraic F E K