English
The within-derivative of a PiLp-valued map is equivalent to the family of within-derivatives of its coordinate maps.
Русский
В рамках внутри-на отображении в PiLp производная эквивалентна множеству внутри-производных координатных отображений.
LaTeX
$$$$ HasFDerivWithinAt f\\, f'\\, t\\, y \\iff \\forall i, HasFDerivWithinAt (fun x => f x i) ((PiLp.proj p E i) \\circ f') \\; t \\; y. $$$$
Lean4
theorem hasFDerivWithinAt_piLp :
HasFDerivWithinAt f f' t y ↔ ∀ i, HasFDerivWithinAt (fun x => f x i) (PiLp.proj _ _ i ∘L f') t y :=
by
rw [← (PiLp.continuousLinearEquiv p 𝕜 E).comp_hasFDerivWithinAt_iff, hasFDerivWithinAt_pi']
rfl