摘要
首先引进一类具有负系数的广义星象函数子类及其广义λ-Hadamard卷积;其次,利用从属关系证明了属于该类函数的充要条件;最后,研究了在函数类上广义λ-Hadamard卷积及其相关特殊卷积的封闭性质.所得结果改进和推广了Choi等人的主要结果,并得到了一些新结果.
In this paper, we first introduce a class of generalized starlike functions with negative coefficients. Secondly, we use the methods of subordination relationship to prove the necessary and sufficient conditions belonging to the above class. Finally, we introduce and investigate closure properties of generalized A-Hadamard product and its related special product. The results obtained extend the main results of Choi et al. in [3] and also get some new results.
引文
[1] Duren P L. Univalent Functions[M]. Grundlehren der Mathematischen Wissenschaften, Vol. 259,Springer-Verlag, New York, Berlin Heidelbergr Tokyo, 1983.
[2] Kumar V. On univalent functions with negative and missing coefficients[J]. Journal of Mathematical Research and Exposition, 1984, 4:27-34.
[3] Choi J H,Kim Y C, and Owa S. Generalizations of Hadamard products of functions with negative coefficients[J]. Journal of Mathematical Analysis and Applications, 1996, 199:495-501.
[4] Janowski W. Some extremal problems for certain families of analytic functions[J]. Ann Polon Math,1973, 28:297-326.
[5] St. Ruscheweyh, Convolution in Geometric Function Theory[M]. Les Presses De Luniversite De Montreal, 1982.