proposition: Lemma mxtrace_is_semi_additive : semi_additive mxtrace.
proof: Proof. split=> [|A B]. - rewrite /mxtrace; under eq_bigr => i _ do rewrite mxE. by rewrite big_const_idem //= addr0. - by rewrite -big_split /=; apply: eq_bigr => i _; rewrite mxE. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg countalg finalg zmodp)