English
Pi-power-series onBall is equivalent to the componentwise hasFPowerSeriesOnBall.
Русский
Pi-представление на шаре эквивалентно компонентному hasFPowerSeriesOnBall.
LaTeX
$$$\\text{hasFPowerSeriesOnBall_pi_iff} : (HasFPowerSeriesOnBall (fun x \\mapsto (f · x)) (pi p) e r) \\Leftrightarrow (\\forall i, HasFPowerSeriesOnBall (f i) (p i) e r)$$$
Lean4
theorem hasFPowerSeriesOnBall_pi_iff (hr : 0 < r) :
HasFPowerSeriesOnBall (fun x ↦ (f · x)) (FormalMultilinearSeries.pi p) e r ↔
∀ i, HasFPowerSeriesOnBall (f i) (p i) e r :=
by
simp_rw [← hasFPowerSeriesWithinOnBall_univ]
exact hasFPowerSeriesWithinOnBall_pi_iff hr