English
EquicontinuousAt F at x0 is equivalent to the infimum range decomposition: EquicontinuousAt F x0 iff ∀ k, EquicontinuousAt F x0.
Русский
ЭконтинуированностьAt при x0 равна бесконечному объединению по iInf.
LaTeX
$$$\\operatorname{EquicontinuousAt} F x_0 \\iff \\forall k, \\operatorname{EquicontinuousAt} F x_0.$$$
Lean4
theorem equicontinuousAt_iInf_rng {u : κ → UniformSpace α'} {F : ι → X → α'} {x₀ : X} :
EquicontinuousAt (uα := ⨅ k, u k) F x₀ ↔ ∀ k, EquicontinuousAt (uα := u k) F x₀ := by
simp only [← equicontinuousWithinAt_univ (uα := _), equicontinuousWithinAt_iInf_rng]