proposition: Lemma le_dlet f g mu nu : mu <=1 nu -> {in dinsupp mu, forall x, f x <=1 g x} -> \dlet_(x <- mu) f x <=1 \dlet_(x <- nu) g x.
proof: Proof. move=> le_mu le_fg x. by apply/(le_trans (le_in_dlet le_fg _))/le_mu_dlet. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum