English
There exists a complete lattice structure on Subalgebra R A obtained via the lifted Galois insertion with gi.
Русский
Существет полная решетка на Subalgebra R A полученная через подъём Галиа-инсерции с gi.
LaTeX
$$$\text{CompleteLattice}(\mathrm{Subalgebra}\; R\; A)$$$
Lean4
/-- Galois insertion between `adjoin` and `coe`. -/
protected def gi : GaloisInsertion (adjoin R : Set A → Subalgebra R A) (↑)
where
choice s hs := (adjoin R s).copy s <| le_antisymm (Algebra.gc.le_u_l s) hs
gc := Algebra.gc
le_l_u S := (Algebra.gc (S : Set A) (adjoin R S)).1 <| le_rfl
choice_eq _ _ := Subalgebra.copy_eq _ _ _