DIFFERENTIAL SUBORDINATION AND SUPERORDINATION OF ANALYTIC FUNCTIONS DEFINED BY A GENERALIZED DERIVATIVE OPERATOR

Abstract

Differential subordination and superordination results are obtained for analytic functions in the open unit disk which are associated with the gen eralized derivative operator Dp α,δ(µ, q, λ)f(z). These results are obtained by investigating appropriate classes of admissible functions. Sandwich-type re sults are also obtained. Some of the results established in this paper would provide extensions to those given in the earlier works.