∀ {α β : Type u_1} [inst : Std.Iterator α Id β] [inst_1 : Std.Iterators.Productive α Id] (it it' : Std.Iter β) (k : ℕ),
  (invImage (fun x => PSigma.casesOn x fun n it => (n, it.finitelyManySkips)) Prod.instWellFoundedRelation).1 ⟨k, it'⟩
    ⟨k.succ, it⟩