By the similar argument as those in the proofs of I51 < ∞, I52 < ∞ and I10 → 0, one can have that I91 → 0, I92 → 0 and I93 → 0. The proof of (2.4) for 1 ≤ q < p and p > 2 is similar to that of Theorem 2.4, here omits the detail. The proof of Theorem 2.5 is completed. □ Acknowledgement. The authors are most grateful to the Editor and anonymous referees for careful reading of the manuscript and valuable suggestions which helped in improving an earlier version of this paper. This paper is supported by the National Nature Science Foundation of China (71963008), the Science and Technology Plan Project of Hunan Province (2016TP1020), Application-Oriented Characterized Disciplines, Double First-Class University Project of Hunan Province (Xiangjiaotong [2018]469), the Scientific Research Fund of Hunan Provincial Education Department (18C0660), the National Statistical Science Research Project of China (2018LY05) and Hunan Provincial Natural Science Foundation of China (2018JJ2006; 2018JJ4024).
