English
Equivalent formulation of ordConnected: s.OrdConnected iff ↑(upperClosure s) ∩ ↑(lowerClosure s) = s.
Русский
Эквивалентная формулировка ordConnected: s.OrdConnected ↔ ↑(upperClosure s) ∩ ↑(lowerClosure s) = s.
LaTeX
$$s.OrdConnected \iff \uparrow(upperClosure s) \cap \uparrow(lowerClosure s) = s$$
Lean4
@[simp]
theorem upperBounds_lowerClosure : upperBounds (lowerClosure s : Set α) = upperBounds s :=
(upperBounds_mono_set subset_lowerClosure).antisymm fun _a ha _b ⟨_c, hc, hcb⟩ ↦ hcb.trans <| ha hc