fact: Definition eval (p:list (Z*Z)) : Z := fold_right (fun x y => x + y) 0%Z (map (fun t => fst t * snd t) p).
imports: Coq.ZArith.ZArith Coq.Lists.List Coq.Setoids.Setoid Coq.Classes.Morphisms Coq.QArith.QArith_base Coq.QArith.Qreduction Coq.QArith.Qround