Document Type : Research Paper
Authors
1 Department of Mathematics, Gorgan Branch, Islamic Azad University, Gorgan, Iran
2 Faculty of Mathematical Sciences, Shahrood University of Technology, P.O. Box 316-36155, Shahrood, Iran
Abstract
In the present paper, we define two subclasses $\Sigma(\lambda, \alpha, \beta)$, $\Sigma_{\mathcal C}(\alpha, \beta)$ of meromorphic univalent functions and subclass $\Sigma_{{\mathcal B},{\mathcal C}}(\alpha, \beta, \lambda)$ of meromorphic bi-univalent functions. Furthermore, we obtain estimates on the general coefficients $|b_n|~(n \ge1)$ for functions in the subclasses $\Sigma(\lambda, \alpha, \beta)$, $\Sigma_{\mathcal C}(\alpha, \beta)$ and estimates for the early coefficients of functions in subclass $\Sigma_{{\mathcal B},{\mathcal C}}(\alpha, \beta, \lambda)$ by associated subordination. The results obtained in this paper would generalize and improve those in related works of several earlier authors.
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