English
Variant stating fderivWithin for the identity function with the fun x => x form, under UniqueDiffWithinAt.
Русский
Вариант для fderivWithin от идентичности в форме fun x => x при условии UniqueDiffWithinAt.
LaTeX
$$$\mathrm{fderivWithin}_{\mathbb{K}}(\mathrm{fun}\;x\;:\;E\to E\;\mapsto x, s, x) = \mathrm{Id}_{\mathbb{K}} E$$$
Lean4
theorem fderivWithin_id' (hxs : UniqueDiffWithinAt 𝕜 s x) :
fderivWithin 𝕜 (fun x : E => x) s x = ContinuousLinearMap.id 𝕜 E :=
fderivWithin_id hxs