(**
   Definition and properties of finite sums and powers.

   WARNING: this file is experimental and likely to change in future releases.
*)

Fixpoint CRsum {R : ConstructiveReals}
         (f:nat -> CRcarrier R) (N:nat) : CRcarrier R :=
  match N with
    | O => f 0%nat
    | S i => CRsum f i + f (S i)
  end.

Lemma sum_eq_R0 : forall {R : ConstructiveReals} (un : nat -> CRcarrier R) (n : nat), (forall k:nat, un k == 0) -> CRsum un n == 0.