proposition: Lemma rep_stepr: forall alpha x y, rep alpha x -> x=y -> rep alpha y.
proof: Proof. intros alpha x y H_rep H_eq; subst x; trivial. Defined.
imports: digits Refining_M Streams_addenda Raxioms RIneq QArithSternBrocot(R_addenda) Fourier_solvable_ineqs