English
IsProperMap f is equivalent to continuity plus the closedness of Prod.map f id on X × Ultrafilter X.
Русский
IsProperMap f эквивалентно непрерывности и замкнутости отображения Prod.map f id на X × Ultrafilter X.
LaTeX
$$IsProperMap f ↔ Continuous f ∧ IsClosedMap (Prod.map f id : X × Ultrafilter X → Y × Ultrafilter X)$$
Lean4
theorem dist_smul_pair (x : α) (y₁ y₂ : β) : dist (x • y₁) (x • y₂) ≤ dist x 0 * dist y₁ y₂ :=
IsBoundedSMul.dist_smul_pair' x y₁ y₂