proposition: Lemma seqn0_as_mask (s : seq R) : seqn0 s = mask (map (fun x => x != 0) s) s.
proof: Proof. by rewrite /seqn0 filter_mask. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path choice fintype order) mathcomp(prime div bigop ssralg poly polydiv polyorder ssrnum zmodp) mathcomp(polyrcf qe_rcf_th complex)