proposition: Lemma eq_dlim f g : f =2 g -> dlim f =1 dlim g.
proof: Proof. move=> eq_f; unlock dlim=> x /=; rewrite /mlim; congr (_ _). by apply/eq_nlim => n; rewrite eq_f. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.classical(boolp classical_sets mathcomp_extra) xfinmap ereal reals discrete topology realseq realsum