proposition: Lemma Qpower_not_0 (a : Q) (n : Z) : ~a==0 -> ~a ^ n == 0.
proof: Proof. intros E1. destruct n; simpl. discriminate. now apply Qpower_not_0_positive. intros E2. destruct (Qpower_not_0_positive a p). easy. now rewrite <-Qinv_involutive, E2. Qed.
imports: Coq.QArith.QArith Coq.ZArith.ZArith Coq.NArith.NArith Coq.QArith.Qpower Coq.QArith.Qround Coq.QArith.Qround Coq.QArith.Qabs CoRN.stdlib_omissions.List