English
If two sets agree on nhds x, their iterated derivatives at x coincide for all orders.
Русский
Если множества совпадают в окрестности x, то их итеративные производные в x совпадают для всех порядков.
LaTeX
$$$\forall h: (nhds x).EventuallyEq s t,\forall n, iteratedFDerivWithin 𝕜 n f s x = iteratedFDerivWithin 𝕜 n f t x$$$
Lean4
theorem iteratedFDerivWithin_eventually_congr_set' (y : E) (h : s =ᶠ[𝓝[{ y }ᶜ] x] t) (n : ℕ) :
iteratedFDerivWithin 𝕜 n f s =ᶠ[𝓝 x] iteratedFDerivWithin 𝕜 n f t := by
induction n generalizing x with
| zero => rfl
| succ n ihn =>
refine (eventually_nhds_nhdsWithin.2 h).mono fun y hy => ?_
simp only [iteratedFDerivWithin_succ_eq_comp_left, (· ∘ ·)]
rw [(ihn hy).fderivWithin_eq_of_nhds, fderivWithin_congr_set' _ hy]