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