proposition: Lemma Rplus_comm : forall r1 r2:R, r1 + r2 = r2 + r1.
proof: Proof. intros. apply Rquot1. do 2 rewrite Rrepr_plus. apply CReal_plus_comm. Qed.
imports: ZArith_base ClassicalDedekindReals ConstructiveCauchyReals ConstructiveCauchyRealsMult ConstructiveRcomplete ConstructiveLUB Rdefinitions