proposition: Lemma sum_upto_O : forall f : nat -> R, Sum_upto f 0 [=] [0].
proof: Proof. algebra. Qed.
imports: CoRN.tactics.CornTac CoRN.algebra.CSums CoRN.algebra.CAbMonoids Coq.Sorting.Permutation CoRN.util.SetoidPermutation Coq.Setoids.Setoid Coq.Classes.Morphisms Coq(Lia)