proposition: Lemma ex_pseries_incr_1 (a : nat -> V) (x : K) : ex_pseries a x -> ex_pseries (PS_incr_1 a) x.
proof: Proof. move => [l Ha] ; exists (scal x l) ; by apply is_pseries_incr_1. Qed.
imports: Coq(Reals Psatz ssreflect) Rcomplements Rbar Lim_seq Lub Hierarchy Continuity Derive Seq_fct Series