English
If the germ of s and t around x coincide, then ContMDiffWithinAt I I' n f s x is equivalent to ContMDiffWithinAt I I' n f t x.
Русский
Если гомогенность окружности s и t около x совпадает, то ContMDiffWithinAt для s равносильна ContMDiffWithinAt для t.
LaTeX
$$$ contMDiffWithinAt_congr_set (h : s =ᶠ[𝓝 x] t) : ContMDiffWithinAt I I' n f s x \leftrightarrow ContMDiffWithinAt I I' n f t x $$$
Lean4
theorem contMDiffWithinAt_inter (ht : t ∈ 𝓝 x) :
ContMDiffWithinAt I I' n f (s ∩ t) x ↔ ContMDiffWithinAt I I' n f s x :=
(contDiffWithinAt_localInvariantProp n).liftPropWithinAt_inter ht