Qed.
Hint Resolve canonical_imp_olist.

(* Specifications: *)
Theorem canonical0 :
forall a b,
ltT b a ->
~ zeroP (A:=A) A0 eqA (n:=n) a ->
~ zeroP (A:=A) A0 eqA (n:=n) b -> canonical (pX a (pX b pO)).