English
The pointwise product of analytic functions is analytic on a set.
Русский
Поточечное произведение аналитических функций аналитично на множестве.
LaTeX
$$$\text{AnalyticOn}_{\mathbb{k}}(f,s) \land \text{AnalyticOn}_{\mathbb{k}}(g,s) \Rightarrow \text{AnalyticOn}_{\mathbb{k}}(\lambda x. f(x) \cdot g(x), s)$$$
Lean4
/-- Multiplication of analytic functions (valued in a normed `𝕜`-algebra) is analytic. -/
@[fun_prop]
theorem mul {f g : E → A} {z : E} (hf : AnalyticAt 𝕜 f z) (hg : AnalyticAt 𝕜 g z) : AnalyticAt 𝕜 (f * g) z :=
hf.fun_mul hg