proposition: Lemma fdistAE x : fdistA x = P (x.1, x.2.1, x.2.2).
proof: Proof. case: x => a [b c]; rewrite /fdistA fdistmapE /= -/(prodA (a, b, c)) big_pred1_inj//. exact: inj_prodA. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup perm matrix) mathcomp(all_algebra vector reals normedtype) mathcomp(mathcomp_extra boolp) mathcomp(Rstruct) ssrR logb realType_ext ssr_ext ssralg_ext bigop_ext