proposition: Lemma snd : d`2 = P`2.
proof: Proof. by rewrite /fdist_snd /d !fdistmap_comp. Qed.
imports: mathcomp(all_ssreflect ssralg matrix) Reals mathcomp(Rstruct) ssrR Reals_ext logb ssr_ext ssralg_ext bigop_ext fdist proba jfdist_cond