proposition: Lemma Var_cast_RV_fdist_rV1 (A : finType) (P : {fdist A}) (X : {RV P -> R}) : `V (@cast_RV_fdist_rV1 _ P _ X) = `V X.
proof: Proof. rewrite !VarE !E_cast_RV_fdist_rV1; congr (_ - _). apply: big_rV_1 => // v; by rewrite fdist_rV1. 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