proposition: Lemma ltrz0 n : (n%:~R < 0 :> R) = (n < 0).
proof: Proof. by rewrite pmulrz_rlt0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)