proposition: Lemma Pr_incl E E' : E \subset E' -> Pr E <= Pr E'.
proof: Proof. move=> H; apply leR_sumRl => a aE //; [ | by move/subsetP : H; exact]. 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