English
In a space with ClosedIicTopology, the upper bounds of the closure of s coincide with those of s: upperBounds(closure s) = upperBounds(s).
Русский
В пространстве с ClosedIicTopology верхние границы closure(s) совпадают с верхними границами s: upperBounds(closure s) = upperBounds(s).
LaTeX
$$upperBounds(closure(s)) = upperBounds(s)$$
Lean4
@[simp]
theorem upperBounds_closure (s : Set α) : upperBounds (closure s : Set α) = upperBounds s :=
ext fun a ↦ by simp_rw [mem_upperBounds_iff_subset_Iic, isClosed_Iic.closure_subset_iff]