intros.
unfold pointwise in |- *.
simpl in |- *.
apply Refl.
Qed.
Hint Resolve pointwise_hd: algebra.

Lemma pointwise_cons :
forall (A B C : Setoid) (a : A) (b : B) (n : Nat)
(v : seq n A) (w : seq n B) (op : Map (cart A B) C),
pointwise op (a;; v) (b;; w) =' op (couple a b);; pointwise op v w
in seq _ _.