fact: Definition mulmor phi psi : 'Mor(M, K) := Morphism (mulmor_proof phi psi).
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