摘要
I. INTRODUCTION AND SOME LEMMASLet{ε<sub>i</sub>} be independent random variables, E（ε<sub>i</sub>） = 0, E（ε<sub>i</sub><sup>2</sup>） =σ<sup>2</sup>, sup E[ε<sub>i</sub>|<sup>r</sup>【∞ for some r】2, {a<sub>ni</sub>} be a double array of constants satisfying proper conditions. Ref. [1] gave
基金
Project supported by the National Youth Natural Science Foundation of China.
