Notation bpow e := (bpow beta e).

Theorem relative_error_N_FLX_round : forall x, (Rabs (round beta (FLX_exp prec) (Znearest choice) x - x) <= /2 * bpow (-prec + 1) * Rabs (round beta (FLX_exp prec) (Znearest choice) x))%R.