English
If f and f1 are eventually equal near x with respect to s, then mdifferentiablewithinAt f equals mdifferentiablewithinAt f1.
Русский
Если f и f1 равны по существу в окрестности x относительно s, то mdifferentiablewithinAt f совпадает с mdifferentiablewithinAt f1.
LaTeX
$$$\text{(nhdsWithin x s).EventuallyEq f_1 f} \Rightarrow MDifferentiableWithinAt I I' f_1 s x \Leftrightarrow MDifferentiableWithinAt I I' f s x$$$
Lean4
theorem mdifferentiableAt_iff (h₁ : f₁ =ᶠ[𝓝 x] f) : MDifferentiableAt I I' f₁ x ↔ MDifferentiableAt I I' f x :=
differentiableWithinAt_localInvariantProp.liftPropAt_congr_iff_of_eventuallyEq h₁