Definition squash_unsquash := K.squash_unsquash.Definition unsquash_squash := K.unsquash_squash.Definition knot_age1 := K.knot_age1.Definition knot_level := K.knot_level.

Lemma pred_ext': forall (p1 p2: pred knot), (forall x: knot * unit, ((fun (p: knot -> Prop) ko => p (fst ko)) oo app_pred) p1 x = ((fun (p: knot -> Prop) ko => p (fst ko)) oo app_pred) p2 x) -> p1 = p2.