fact: Record Z4 : Set := {z4crr :> Z * Z * (Z * Z); z4prf : (0 <= fst (fst z4crr))%Z /\ (0 <= snd (fst z4crr))%Z /\ (0 <= fst (snd z4crr))%Z /\ (0 <= snd (snd z4crr))%Z}.
imports: QArithSternBrocot(Merge_Order) Coq(Wf_nat)