(* This file was originally generated by why.
   It can be modified; only the generated parts will be overwritten. *)

Require Import Why.

Proof.
intuition.
Save.

Proof.
intuition.
subst.
ring.
assert (h: 2 * s = i * (i + 1)). assumption.
rewrite h; ring.
Save.

Proof.
intuition.
assert (i=n). omega. subst; auto with arith.
Save.

(*Why axiom*) Lemma distr_left :
  (forall (a:Z),
   (forall (b:Z), (forall (c:Z), (a * (b + c)) = (a * b + a * c)))).
Admitted.

(*Why axiom*) Lemma distr_right :
  (forall (a:Z),
   (forall (b:Z), (forall (c:Z), ((b + c) * a) = (b * a + c * a)))).
Admitted.

