English
If f and g are continuous functions, then the map a ↦ Fin.snoc(f(a), g(a)) is continuous.
Русский
Если f и g непрерывны, то отображение a ↦ Fin.snoc(f(a), g(a)) непрерывно.
LaTeX
$$$\\displaystyle \\text{Continuous}\\bigl( a \\mapsto \\mathrm{Fin.snoc}( f(a), g(a) ) \\bigr).$$$
Lean4
theorem finSnoc {f : X → ∀ j : Fin n, A j.castSucc} {g : X → A (Fin.last _)} (hf : Continuous f) (hg : Continuous g) :
Continuous fun a => Fin.snoc (f a) (g a) :=
continuous_iff_continuousAt.2 fun _ => hf.continuousAt.finSnoc hg.continuousAt