fact: Fixpoint pring_aux (p : positive) (pow2 : R) {struct p} : R := match p with | xH => pow2 | xO p => pring_aux p (Two[*]pow2) | xI p => pow2[+]pring_aux p (Two[*]pow2) 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)