English
If nhdsWithin x s ω1 ω2 holds, then extDerivWithin ω1 s x and extDerivWithin ω2 s x are also equal in nhdsWithin x s.
Русский
Если выполняется эквивалентность nhdsWithin x s между ω1 и ω2, то и их extDerivWithin ω с x равны в той же окрестности.
LaTeX
$$$ (\\nhdsWithin x\, s).EventuallyEq\, ω_1\, ω_2 \\rightarrow (\\nhdsWithin x\, s).EventuallyEq\\,(extDerivWithin(ω_1\, s))\\,(extDerivWithin(ω_2\, s)) $$$
Lean4
protected theorem extDeriv (h : ω₁ =ᶠ[𝓝 x] ω₂) : extDeriv ω₁ =ᶠ[𝓝 x] extDeriv ω₂ :=
by
simp only [← nhdsWithin_univ, ← extDerivWithin_univ] at *
exact h.extDerivWithin