Harmonic functions with missing coefficients

Abstract

In the paper we introduce the classes of functions with missing coefficients defined by generalized Ruscheweyh derivatives and we show that they can be presented as dual sets. Moreover, by using extreme points theory, we obtain estimations of classical convex functionals on the defined classes of functions. Some applications of the main results are also considered.

Keywords

• Harmonic functions,Subordination,Missing coefficients,Ruscheweyh operator,Dual sets,Correlated coefficients

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