Section Dickson.
Variable A B : Set.
Variable lt : Rel A.
Variable R : Rel B.
Variable wfgt : well_founded lt.
Variable declt : DecRel A lt.
Variable wR : WR B R.
Definition leq (a b : A) := ~ lt b a.
Definition GBarlR := GRBar (A * B) (ProdRel A B leq R).
Definition sndL := map (fun p : A * B => snd p).
Definition MinD :=
Min (A * B) (fun p q : A * B => lt (fst p) (fst q)) (ProdRel A B leq R).
Definition prod_lt (a b : A * B) := lt (fst a) (fst b).

Lemma WFlem1 : well_founded prod_lt.