proposition: Lemma is_lim_seq_minus (u v : nat -> R) (l1 l2 l : Rbar) : is_lim_seq u l1 -> is_lim_seq v l2 -> is_Rbar_minus l1 l2 l -> is_lim_seq (fun n => u n - v n) l.
proof: Proof. intros H1 H2 Hl. eapply is_lim_seq_plus ; try eassumption. apply -> is_lim_seq_opp ; apply H2. Qed.
imports: Coq(Reals Psatz ssreflect) Rcomplements Rbar Lub Markov Hierarchy