English
For nonempty β, EventuallyConst f l is equivalent to the existence of x with Tendsto f l (pure x).
Русский
Для непустого β условие EventuallyConst f l эквивалентно существованию x, при котором Tendsto f l (pure x).
LaTeX
$$$\\\\forall {f} {l} [Nonempty B],\\\\; (EventuallyConst f l) \\\\Leftrightarrow \\\\exists x, Tendsto f l (\\\\text{pure } x)$$$
Lean4
theorem eventuallyConst_pred' {p : α → Prop} : EventuallyConst p l ↔ (p =ᶠ[l] fun _ ↦ False) ∨ (p =ᶠ[l] fun _ ↦ True) :=
by simp only [eventuallyConst_iff_exists_eventuallyEq, «Prop».exists_iff]