English
If f: E → F →L[𝕜] G and g: E → F are ContDiff 𝕜 n, then x ↦ (f x)(g x) is ContDiff 𝕜 n.
Русский
Если f: E → F →L[𝕜] G и g: E → F гладкие порядка n, то x ↦ (f x)(g x) гладко порядка n.
LaTeX
$$$\mathrm{ContDiff}_{\mathbb{k}}\ n\ f \Rightarrow \mathrm{ContDiff}_{\mathbb{k}}\ n\ g \Rightarrow \mathrm{ContDiff}_{\mathbb{k}}\ n\ (x \mapsto (f x)(g x)).$$$
Lean4
@[fun_prop]
theorem smulRight {f : E → StrongDual 𝕜 F} {g : E → G} (hf : ContDiff 𝕜 n f) (hg : ContDiff 𝕜 n g) :
ContDiff 𝕜 n fun x => (f x).smulRight (g x) :=
isBoundedBilinearMap_smulRight.contDiff.comp₂ (g := fun p => p.1.smulRight p.2) hf hg