“…Using Lemma 3.6, we can apply Theorem 3.1 in [7] to (T, X, M, T M) so that any A ∈ R(C, T ) ∩ M is a Darling-Kac set for T whose return time process is continued fraction mixing and T is pointwise dual ergodic, i.e., for any f ∈ L 1 (µ) lim n→∞ [2]). Then (3.3-1)-(3.3-2) follow from the results which were established in [1], [4] and [34] (cf. [7]).…”