proposition: Lemma fdist_proj23E x : fdist_proj23 x = \sum_(a in A) P (a, x.1, x.2).
proof: Proof. by rewrite /fdist_proj23 fdist_sndE; apply eq_bigr => a _; rewrite fdistAE. 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