English
The HasFPowerSeriesOnBall instance for the bilinear function x ↦ f x.1 x.2 exists with the radius ∞, reflecting global analyticity in both variables.
Русский
Существование HasFPowerSeriesOnBall для билинейной функции x ↦ f x.1 x.2 с радиусом ∞ отражает глобальную аналитичность по обеим переменным.
LaTeX
$$$ HasFPowerSeriesOnBall (\lambda x : E×F => f x.1 x.2) (f.fpowerSeriesBilinear x) x \infty$$$
Lean4
protected theorem hasFPowerSeriesOnBall_bilinear (f : E →L[𝕜] F →L[𝕜] G) (x : E × F) :
HasFPowerSeriesOnBall (fun x : E × F => f x.1 x.2) (f.fpowerSeriesBilinear x) x ∞ :=
{ r_le := by simp
r_pos := ENNReal.coe_lt_top
hasSum := fun _ =>
(hasSum_nat_add_iff' 3).1 <|
by
simp only [Finset.sum_range_succ, Prod.fst_add, Prod.snd_add, f.map_add_add]
simp [fpowerSeriesBilinear, hasSum_zero] }