Certain subclasses of meromorphically p-valent functions with positive or negative coefficients

Making use a linear operator, we introduce two novel subclasses R(n, p, lambda, alpha) and C(n, p, lambda, alpha) of meromorphically p-valent functions with positive and negative coefficients, respectively. The main object of this paper is to investigate the various important properties and characteristics of these subclasses of meromorphically p-valent functions. We also derive many interesting results for the Hadamard products of functions belonging to the classes R(n, p, lambda, alpha) and C(n, p, lambda, alpha). (c) 2007 Elsevier Ltd. All rights reserved.