English
The Cartesian product of analytic functions is analytic.
Русский
Картезианово произведение аналитических функций аналитично.
LaTeX
$$$(\\text{AnalyticOnNhd 𝕜 f s}) \\land (\\text{AnalyticOnNhd 𝕜 g s}) \\Rightarrow (\\text{AnalyticOnNhd 𝕜} (fun x \\mapsto (f x, g x)) s)$$$
Lean4
/-- The Cartesian product of analytic functions is analytic. -/
theorem prod {f : E → F} {g : E → G} {s : Set E} (hf : AnalyticOnNhd 𝕜 f s) (hg : AnalyticOnNhd 𝕜 g s) :
AnalyticOnNhd 𝕜 (fun x ↦ (f x, g x)) s := fun x hx ↦ (hf x hx).prod (hg x hx)