proposition: Lemma mulz_gcdr m n p : `|m|%:Z * gcdz n p = gcdz (m * n) (m * p).
proof: Proof. by rewrite -PoszM muln_gcdr -!abszM. 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)