proposition: Lemma Rplus_ge_gt_compat : forall r1 r2 r3 r4, r1 >= r2 -> r3 > r4 -> r1 + r3 > r2 + r4.
proof: Proof. now intros r1 r2 r3 r4 H%Rge_le H'; apply Rplus_le_lt_compat. Qed.
imports: RelationClasses Raxioms Rpow_def ZArith ZArithRing RealField