proposition: Lemma le1_dlim f : forall x, dlim f x <= 1.
proof: Proof. by move=> x; case: dlimP => // _; apply/ler01. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum