English
The upper bounds of supClosure(s) are exactly the upper bounds of s.
Русский
верхние границы supClosure(s) совпадают с верхними границами s.
LaTeX
$$$\\mathrm{upperBounds}(\\operatorname{supClosure}(s)) = \\mathrm{upperBounds}(s)$$$
Lean4
@[simp]
theorem upperBounds_supClosure (s : Set α) : upperBounds (supClosure s) = upperBounds s :=
(upperBounds_mono_set subset_supClosure).antisymm <|
by
rintro a ha _ ⟨t, ht, hts, rfl⟩
exact sup'_le _ _ fun b hb ↦ ha <| hts hb