fact: Definition mul (p q:list (Z*Z)) : list (Z*Z) := flat_map (fun t => map (fun t' => (fst t * fst t', snd t * snd t')) q) p.
imports: Coq.ZArith.ZArith Coq.Lists.List Coq.Setoids.Setoid Coq.Classes.Morphisms Coq.QArith.QArith_base Coq.QArith.Qreduction Coq.QArith.Qround