English
DifferentiableWithinAt 𝕜 f s x implies the same equality as in 𝕜′, and with hs unique diff, 𝕜 differentiability is equivalent to the existence of g′ with g′.restrictScalars 𝕜 = fderivWithin 𝕜 f s x.
Русский
Дифференцируемость внутри s по 𝕜 эквивалентна существованию 𝕜′-производной, ограничения которой по скалярам совпадают с fderivWithin 𝕜 f s x.
LaTeX
$$DifferentiableWithinAt 𝕜 f s x ↔ (UniqueDiffWithinAt 𝕜 s x → (DifferentiableWithinAt 𝕜' f s x ↔ ∃ g' : E →L[𝕜'] F, g'.restrictScalars 𝕜 = fderivWithin 𝕜 f s x))$$
Lean4
protected theorem ne_iff {p q : FormalMultilinearSeries 𝕜 E F} : p ≠ q ↔ ∃ n, p n ≠ q n :=
Function.ne_iff