Notation SwapProd := (swapprod A R).

(* Specifications: *)
Lemma swap_Acc : forall x y:A, Acc SwapProd (x, y) -> Acc SwapProd (y, x).
Lemma Acc_swapprod : forall x y:A, Acc R x -> Acc R y -> Acc SwapProd (x, y).
Lemma wf_swapprod : well_founded R -> well_founded SwapProd.