fact: Fixpoint List_Sum_upto (l : list R) (n : nat) {struct n} : R := match n with | O => [0] | S x => RList_Mem l x[+]List_Sum_upto l x end.
imports: CoRN.tactics.CornTac CoRN.algebra.CSums CoRN.algebra.CAbMonoids Coq.Sorting.Permutation CoRN.util.SetoidPermutation Coq.Setoids.Setoid Coq.Classes.Morphisms Coq(Lia)