proposition: Lemma prod_types_app i (A B : prod_types) : A = B -> A i = B i.
proof: Proof. by move=> ->. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum matrix) mathcomp(Rstruct) Reals ssrR Reals_ext logb ssr_ext ssralg_ext bigop_ext fdist proba