∀[T:Type]. ∀[x:colist(T)]. (isaxiom(x) ∈ 𝔹)
{ (InstLemma `colist-ext` [] THEN ParallelLast' THEN D -1 THEN Auto) }
1. T : Type
2. colist(T) ⊆r (Unit ⋃ (T × colist(T)))
3. (Unit ⋃ (T × colist(T))) ⊆r colist(T)
4. x : colist(T)
⊢ isaxiom(x) ∈ 𝔹