proposition: Lemma pow_1_odd : forall n:nat, (-1) ^ S (2 * n) = -1.
proof: Proof. intro; replace (S (2 * n)) with (2 * n + 1)%nat by ring. rewrite pow_add; rewrite pow_1_even; simpl; ring. Qed.
imports: ArithRing Rdefinitions Raxioms RIneq Rpow_def R_Ifp Rbasic_fun R_sqr SplitAbsolu SplitRmult ArithProp Zpower Ztac