proposition: Lemma series_addn m n : series (n + m)%N = series m + \sum_(m <= k < n + m) u_ k.
proof: Proof. by rewrite seriesEnat/= -big_cat_nat// leq_addl. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(set_interval) reals ereal signed topology normedtype landau