proposition: Lemma mulmorA (psi : 'Mor(M,N)) (phi : 'Mor(N,P)) (kapa : 'Mor(P,Q)) : psi ** (phi ** kapa) = (psi ** phi) ** kapa.
proof: Proof. by apply: val_inj; rewrite /= mulmxA. 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