proposition: Lemma mulmor0 (phi : 'Mor(M,P)) : phi ** 0 = 0 :> 'Mor(M, Q).
proof: Proof. by apply: val_inj; rewrite /= mulmx0. 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