Bi-concave Functions Defined by Al-Oboudi Differential Operator

Abstract

. The purpose of the present paper is to introduce a class D n Σ; δ C 0 ( α ) of bi-concave functions defined by Al-Oboudi differential operator. We find estimates on the Taylor-Maclaurin coefficients | a 2 | and | a 3 | for functions in this class. Several consequences of these results are also pointed out in the form of corollaries.