English
For CommGroup α with partial order and IsOrderedMonoid structure, there is an equivalence between IsBoundedUnder(≤) of the inverse of u and IsBoundedUnder(≥) of u.
Русский
Для комм-группы с частичным порядком и структурой IsOrderedMonoid существует эквивалентность между IsBoundedUnder(≤) инверсии u и IsBoundedUnder(≥) u.
LaTeX
$$$(OrderIso.inv\ α).isBoundedUnder_ge_comp$$$
Lean4
@[to_additive (attr := simp)]
theorem isBoundedUnder_le_inv [CommGroup α] [PartialOrder α] [IsOrderedMonoid α] {l : Filter β} {u : β → α} :
(IsBoundedUnder (· ≤ ·) l fun x => (u x)⁻¹) ↔ IsBoundedUnder (· ≥ ·) l u :=
(OrderIso.inv α).isBoundedUnder_ge_comp