Module K := K'.
Arguments unsquash_inj [k1 k2] _.
Arguments unsquash_approx [k n Fp] _.

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.