English
If f: X → Z and g: X → Fin n → Z are continuous at x, then a ↦ Matrix.vecCons(f(a))(g(a)) is continuous at x.
Русский
Пусть f: X → Z и g: X → Fin n → Z непрерывны в x; тогда a ↦ Matrix.vecCons(f(a))(g(a)) непрерывна в x.
LaTeX
$$$\\text{ContinuousAt } f\\ x \\land \\text{ContinuousAt } g\\ x \\Rightarrow \\text{ContinuousAt}(a \\mapsto \\mathrm{Matrix.vecCons}(f(a))(g(a)))\\ x$$$
Lean4
theorem matrixVecCons {f : X → Z} {g : X → Fin n → Z} {x : X} (hf : ContinuousAt f x) (hg : ContinuousAt g x) :
ContinuousAt (fun a => Matrix.vecCons (f a) (g a)) x :=
hf.finCons hg