English
If f is differentiable on s and nonvanishing on closure s, then f⁻¹ is differentiable on s.
Русский
Если f дифференцируема на s и не обращается в нуль в замыкании s, то f⁻¹ дифференцируема на s.
LaTeX
$$$\forall f:\, \text{DiffContOnCl}(𝕜, f, s) \land \forall x ∈ closure(s), f(x) ≠ 0 \Rightarrow \text{DiffContOnCl}(𝕜, f^{-1}, s).$$$
Lean4
theorem extDerivWithin_smul (c : 𝕜) (ω : E → E [⋀^Fin n]→L[𝕜] F) (hsx : UniqueDiffWithinAt 𝕜 s x) :
extDerivWithin (c • ω) s x = c • extDerivWithin ω s x := by
simp [extDerivWithin, fderivWithin_const_smul_of_field, hsx, alternatizeUncurryFin_smul]