proposition: Lemma E_const_RV k : `E (const_RV P k) = k.
proof: Proof. by rewrite /Ex /const_RV /= -big_distrr /= FDist.f1 mulR1. 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