proposition: Lemma fdistAX12 : ((fdistX (fdistA P))`1)`2 = P`2.
proof: Proof. by rewrite /fdist_snd /fdist_fst /fdistX !fdistmap_comp. 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