English
If a function is analytic on neighborhood sets around every point of s (AnalyticOnNhd), then it is analytic on s (AnalyticOn).
Русский
Если функция аналитична на окрестностях каждой точки множества s (AnalyticOnNhd), то она аналитична на множестве s (AnalyticOn).
LaTeX
$$$\text{AnalyticOnNhd}_{\mathcal{K}}(f,s) \Rightarrow \text{AnalyticOn}_{\mathcal{K}}(f,s)$$$
Lean4
theorem analyticOn (hf : AnalyticOnNhd 𝕜 f s) : AnalyticOn 𝕜 f s := fun x hx ↦ (hf x hx).analyticWithinAt