proposition: Lemma fdist_proj13_RV3 : fdist_proj13 `p_[% X, Y, Z] = `p_[% X, Z].
proof: Proof. by rewrite /fdist_proj13 /fdist_snd /fdistA /dist_of_RV /fdistC12 !fdistmap_comp. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum matrix) mathcomp(Rstruct reals) Reals Lra ssrR Reals_ext realType_ext logb ssr_ext ssralg_ext bigop_ext fdist