English
If r is reflexive, then for any filter l on β and any a in α, the constant function mapping every element to a is bounded under r along l.
Русский
Пусть r рефлексивна. Тогда для любого фильтра l на β и любого a ∈ α константная функция, возвращающая a, ограничена по r вдоль l.
LaTeX
$$$ [IsRefl\ α\ r] \Rightarrow \forall l : Filter\, β,\ a : α, IsBoundedUnder r l (\text{const}_{a}) $$$
Lean4
theorem isBoundedUnder_const [IsRefl α r] {l : Filter β} {a : α} : IsBoundedUnder r l fun _ => a :=
⟨a, eventually_map.2 <| Eventually.of_forall fun _ => refl _⟩