∀ {α : Type u} (r : α → α → Prop) [inst : IsWellOrder α r]
  (f : (a : Ordinal.{u}) → a < Ordinal.type r → Ordinal.{max u v}),
  (Ordinal.type r).blsub f = Ordinal.lsub fun a => f ((Ordinal.typein r).toRelEmbedding a) ⋯