proposition: Lemma nmulrn (R : zmodType) (x : R) (n : nat) : x *- n = x *~ - n%:Z.
proof: Proof. by case: n=> [] //; rewrite ?oppr0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)