Lemmas about List
s and Set.range
#
In this file we prove lemmas about range of some operations on lists.
@[simp]
theorem
Set.range_list_nthLe
{α : Type u_1}
(l : List α)
:
(Set.range fun (k : Fin (List.length l)) => List.nthLe l ↑k (_ : ↑k < List.length l)) = {x : α | x ∈ l}
If each element of a list can be lifted to some type, then the whole list can be lifted to this type.