English
If Tendsto (f(x) · C) to +∞, then Tendsto (f(x) · C') to +∞ implies Tendsto f to +∞ (duality via dual order).
Русский
Если Tendsto (f(x) · C) → +∞, то Tendsto (f(x) · C') → +∞ для констант C', выводит Tendsto f → +∞ (дуальная формулировка).
LaTeX
$$$\\operatorname{Tendsto}(\\lambda x. f(x) \\cdot C)\\ l\\ atTop \\Rightarrow \\operatorname{Tendsto} f\\ l\\ atTop$$$
Lean4
@[to_additive]
theorem atBot_of_const_le_mul (hf : ∃ C, ∀ x, C ≤ f x) (hfg : Tendsto (fun x ↦ f x * g x) l atBot) :
Tendsto g l atBot :=
Tendsto.atTop_of_le_const_mul (M := Mᵒᵈ) hf hfg