English
For a closure operator c, the associated Galois insertion recovers c from its GC: c.gi.gc.closureOperator = c.
Русский
Для замыкательного оператора c соответствующая вставка Галуа восстанавливает его: c.gi.gc.closureOperator = c.
LaTeX
$$$c.gi.gc.closureOperator = c$$$
Lean4
/-- The Galois insertion associated to a closure operator can be used to reconstruct the closure
operator.
Note that the inverse in the opposite direction does not hold in general. -/
@[simp]
theorem closureOperator_gi_self [PartialOrder α] (c : ClosureOperator α) : c.gi.gc.closureOperator = c :=
by
ext x
rfl