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