English
The pointwise maximum of two continuous functions into a lattice with ContinuousSup is continuous.
Русский
Пусть две непрерывные функции в решетке сходятся; максимум по каждому аргументу непрерывен.
LaTeX
$$$\\text{Continuous}(f) \\land \\text{Continuous}(g) \\Rightarrow \\text{Continuous}(x \\mapsto f(x) \\lor g(x))$$$
Lean4
@[continuity, fun_prop]
theorem sup [Max L] [ContinuousSup L] {f g : X → L} (hf : Continuous f) (hg : Continuous g) :
Continuous fun x => f x ⊔ g x :=
continuous_sup.comp (hf.prodMk hg :)