proposition: Fact dvdz_zmod_closed d : zmod_closed (dvdz d).
proof: Proof. split=> [|_ _ /dvdzP[p ->] /dvdzP[q ->]]; first exact: dvdz0. by rewrite -mulrBl dvdz_mull. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop prime order) mathcomp(ssralg poly ssrnum ssrint archimedean rat matrix) mathcomp(polydiv perm zmodp mxalgebra vector)