proposition: Lemma gcdzMl n m : gcdz n (m * n) = `|n|%:Z.
proof: Proof. by rewrite -[m * n]addr0 gcdzMDl gcdz0. 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)