English
In a normed space setting, composition preserves ContMDiffWithinAt under ContDiffWithinAt of the outer map and ContMDiffWithinAt of the inner map.
Русский
В условиях нормированного пространства композиция сохраняет ContMDiffWithinAt при ContDiffWithinAt внешней функции и внутри。
LaTeX
$$$\text{ContDiffWithinAt } 𝕜 n g t (f x) \land \text{ContMDiffWithinAt } I 𝓘(𝕜, F) n f s x \Rightarrow \ ContMDiffWithinAt I 𝓘(𝕜, F') n (g \circ f) s x$$$
Lean4
theorem comp_contMDiffAt {g : F → F'} {f : M → F} {x : M} (hg : ContDiff 𝕜 n g) (hf : ContMDiffAt I 𝓘(𝕜, F) n f x) :
ContMDiffAt I 𝓘(𝕜, F') n (g ∘ f) x :=
hg.comp_contMDiffWithinAt hf