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Differential subordinations using Ruscheweyh derivative and a multiplier transformation. (English) Zbl 1358.30004

Summary: The author derives several interesting differential subordination results. These subordinations are established by means of a differential operator obtained using Ruscheweyh derivative \(R^m(z)\) and the multiplier transformations \(I(m,\lambda,l) f(z)\) namely \(RI^\alpha_{m,\lambda,l}\) the operator given by \(RI^\alpha_{m,\lambda,l}:{\mathcal A}_n\to{\mathcal A}_n\), \(RI^\alpha_{m,\lambda,l} f(z)= (1-\alpha)R^m f(z)+ \alpha I(m,\lambda,l) f(z)\), for \(z\in U\), \(m\in\mathbb{N}\), \(l\geq 0\) and \({\mathcal A}_n=\{f\in{\mathcal H}(U): f(z)= z+ a_{n+1} z^{n+1}+\cdots+ z\in U\}\).
A number of interesting consequences of some of these subordination results are discussed. Relevant connections of some of the new results obtained in this paper with those in earlier works are also provided.

MSC:

30C45 Special classes of univalent and multivalent functions of one complex variable (starlike, convex, bounded rotation, etc.)
34A40 Differential inequalities involving functions of a single real variable