English
Dual notion to Galois insertion giving a coinsertion between the same two functors.
Русский
Двойственная концепция к Galо insertion даёт Coinsertion между теми же двумя отображениями.
LaTeX
$$galoisCoinsertionIntermediateFieldSubgroup$$
Lean4
/-- The Galois correspondence as a `GaloisCoinsertion`. -/
def galoisCoinsertionIntermediateFieldSubgroup [FiniteDimensional F E] [IsGalois F E] :
GaloisCoinsertion
(OrderDual.toDual ∘ (IntermediateField.fixingSubgroup : IntermediateField F E → Subgroup (E ≃ₐ[F] E)))
((IntermediateField.fixedField : Subgroup (E ≃ₐ[F] E) → IntermediateField F E) ∘ OrderDual.toDual) :=
OrderIso.toGaloisCoinsertion intermediateFieldEquivSubgroup