proposition: Lemma intr_eq0 n : (n%:~R == 0 :> R) = (n == 0).
proof: Proof. by rewrite -(mulr0z 1) (inj_eq (mulrIz _)) // oner_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)