proposition: Lemma mul0mor (phi : 'Mor(M,P)) : 0 ** phi = 0 :> 'Mor(N,P).
proof: Proof. by apply: val_inj; rewrite /= mul0mx. 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