English
The identity function on a preorder is a lower adjoint to itself.
Русский
Единичная функция на полном порядке является нижним сюрьом к самой себе.
LaTeX
$$$\\\\text{protected def } id [Preorder {\\\\alpha}] : \\text{LowerAdjoint} (id : {\\\\alpha} → {\\\\alpha})$$$
Lean4
/-- The identity function as a lower adjoint to itself. -/
@[simps]
protected def id [Preorder α] : LowerAdjoint (id : α → α)
where
toFun x := x
gc' := GaloisConnection.id