proposition: Lemma fdist_proj13E x : fdist_proj13 x = \sum_(b in B) P (x.1, b, x.2).
proof: Proof. by rewrite /fdist_proj13 fdist_sndE; apply eq_bigr => b _; rewrite fdistAE fdistC12E. 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