proposition: Lemma pr_eq_ge0 (X : {RV P -> A}) (a : A) : 0 <= `Pr[ X = a].
proof: Proof. by rewrite pr_eqE. 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