English
If f and g are analytic within at s around x, then the map x ↦ (f(x), g(x)) is analytic within at s around x.
Русский
Если f и g аналитичны внутри s вокруг x, то отображение x ↦ (f(x), g(x)) аналитично внутри s вокруг x.
LaTeX
$$$\text{AnalyticWithinAt}(f, s, x) \land \text{AnalyticWithinAt}(g, s, x) \Rightarrow \text{AnalyticWithinAt}(x \mapsto (f(x), g(x)), s, x)$$$
Lean4
theorem add (hf : AnalyticOnNhd 𝕜 f s) (hg : AnalyticOnNhd 𝕜 g s) : AnalyticOnNhd 𝕜 (f + g) s := fun z hz =>
(hf z hz).add (hg z hz)