∀ (F : Type u) (E : Type v) [inst : Field F] [inst_1 : Field E] [inst_2 : Algebra F E] (K : Type w) [inst_3 : Field K]
  [inst_4 : Algebra F K] [inst_5 : Algebra K E] [inst_6 : IsScalarTower F K E],
  (separableClosureOperator F E).IsClosed (IntermediateField.restrictScalars F (separableClosure K E))