English
Same as previous, asserting constant germ after composing with Subtype.val on a subtype.
Русский
То же самое: константный герм после композиции с Subtype.val на подтипе.
LaTeX
$${hf : (f : \mathrm{Germ}(\mathcal N (x:X)) Y).IsConstant} \Rightarrow ((f \circ \mathrm{Subtype.val} : s → Y) : \mathrm{Germ}(\mathcal N x) Y).IsConstant$$
Lean4
theorem isConstant_comp_subtype {s : Set X} {f : X → Y} {x : s} (hf : (f : Germ (𝓝 (x : X)) Y).IsConstant) :
((f ∘ Subtype.val : s → Y) : Germ (𝓝 x) Y).IsConstant :=
isConstant_comp_tendsto hf continuousAt_subtype_val