(* Autor(s): Andrej Dudenhefner (1) Affiliation(s): (1) Saarland University, Saarbrücken, Germany *)
Local Notation "p ≃ q" := (poly_eq p q) (at level 65).

Lemma poly_add_assoc {p q r} : poly_add p (poly_add q r) ≃ poly_add (poly_add p q) r.