A class of integral operators preserving subordination and superordination for meromorphic functions

摘要

The purpose of the present paper is to investigate several subordination- and superordination-preserving properties of a certain class of integral operators, which are defined on the space of meromorphic functions in the punctured open unit disk. The sandwich-type theorem for these integral operators is also presented. Moreover, we consider an application of the subordination and superordination theorem to the Gauss hypergeometric function. (C) 2007 Elsevier Inc. All rights reserved.