English
For any sets S and T in a metric space, the Hausdorff distance between closures equals the distance between the original sets.
Русский
Для любых множеств S и T в метрическом пространстве расстояние Хаусдорфа между их замыканиями равно расстоянию между самими множествами.
LaTeX
$$$\\operatorname{hausdorffDist}(\\overline{s}, \\overline{t}) = \\operatorname{hausdorffDist}(s, t)$$$
Lean4
/-- The Hausdorff distances between two sets and their closures coincide. -/
theorem hausdorffDist_closure : hausdorffDist (closure s) (closure t) = hausdorffDist s t := by simp [hausdorffDist]