English
The scalar action of F on E factors through the bottom intermediate field, giving a consistent IsScalarTower structure.
Русский
Действие скаляров F на E факторизуется через нижнее промежуточное поле, образуя согласованную структуру IsScalarTower.
LaTeX
$$$ IsScalarTower (\\bot : \\text{IntermediateField}(F,E)) F E $$$
Lean4
instance isScalarTower_over_bot : IsScalarTower (⊥ : IntermediateField F E) F E :=
IsScalarTower.of_algebraMap_eq
(by
intro x
obtain ⟨y, rfl⟩ := (botEquiv F E).symm.surjective x
rw [coe_algebraMap_over_bot, (botEquiv F E).apply_symm_apply, botEquiv_symm,
IsScalarTower.algebraMap_apply F (⊥ : IntermediateField F E) E])