Bi-Concave Functions Involving a Differential Operator.

The purpose of the present paper is to introduce a class Dκ,α λ,δ C0 (ß) of bi-concave functions defined by a differential operator. We find estimates on the Taylor-Maclaurin coefficients |a2 | and |a3 | for functions in this class. Several consequences of these results are also pointed out in the form of corollaries. [ABSTRACT FROM AUTHOR]