proposition: Lemma f1 : \sum_(b in D) f b = 1.
proof: Proof. rewrite -(FSDist.f1 P) big_seq_fsetE /=; apply eq_bigr => a; by rewrite ffunE. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum) mathcomp(finmap) Reals mathcomp(mathcomp_extra) mathcomp(classical_sets boolp cardinality Rstruct reals) mathcomp(ereal topology esum measure probability) ssrR realType_ext Reals_ext ssr_ext ssralg_ext bigop_ext fdist convex