proposition: Lemma dvdmx_morphism (phi : 'Mor(M, N)) : (pres N %| pres M *m phi).
proof: Proof. by case: phi. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice matrix bigop zmodp mxalgebra poly) ssrcomplements stronglydiscrete coherent edr