proposition: Lemma Rlt_ge_dec : forall r1 r2, {r1 < r2} + {r1 >= r2}.
proof: Proof. intros r1 r2; destruct (Rlt_le_dec r1 r2) as [Hlt | H%Rle_ge]. - now left. - now right. Qed.
imports: RelationClasses Raxioms Rpow_def ZArith ZArithRing RealField