English
If α is nonempty, directed under ≥, and β is finite, then for any f : Filter β and u : β → α, IsBoundedUnder (≥) f u.
Русский
Пусть α непусто и направлено относительно ≥, β конечно; тогда для любого фильтра f на β и отображения u: β → α, u ограничен снизу по ≥ вдоль f.
LaTeX
$$$ [Nonempty α] [IsDirected α (\ge)] [Finite β] \Rightarrow IsBoundedUnder (\ge) f u $$$
Lean4
theorem ge_of_finite [Nonempty α] [IsDirected α (· ≥ ·)] [Finite β] {f : Filter β} {u : β → α} :
IsBoundedUnder (· ≥ ·) f u :=
(Set.toFinite _).bddBelow.isBoundedUnder_of_range