proposition: Lemma Pr_1 E : Pr E <= 1.
proof: Proof. rewrite (_ : 1 = GRing.one _)//. rewrite -(FDist.f1 P); apply leR_sumRl => // a _. by apply/RleP; rewrite lexx. 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