proposition: Lemma lef_dnull {R : realType} {T : choiceType} (mu : {distr T / R}) : dnull <=1 mu.
proof: Proof. by move=> x; rewrite dnullE ge0_mu. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum