fact: Fixpoint flatten {A:Type} (t: Monoid_Exp A) : Monoid_Exp A := match t with | Mul_node t t' => flatten_aux t (flatten t') | One_node => One_node | X => Mul_node X One_node end.
imports: Coq(Relations RelationClasses Lia List) Param(Param) additions(More_on_positive)