proposition: Lemma inv_nexp_odd : forall (x : R) n, Nat.Odd n -> [--]x[^]n [=] [--] (x[^]n).
proof: Proof. intros x [| n] H; [apply Nat.odd_spec in H; discriminate H |]. apply Nat.Odd_succ in H. astepl ( [--]x[*] [--]x[^]n). astepl ( [--]x[*]x[^]n). Step_final ( [--] (x[*]x[^]n)). 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)