proposition: Lemma mulr2z n : n *~ 2 = n + n.
proof: Proof. exact: mulr2n. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)