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Subclasses of uniformly starlike and convex functions defined by certain integral operator - MaRDI portal

Subclasses of uniformly starlike and convex functions defined by certain integral operator (Q882692)

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scientific article; zbMATH DE number 5156824
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Subclasses of uniformly starlike and convex functions defined by certain integral operator
scientific article; zbMATH DE number 5156824

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    Subclasses of uniformly starlike and convex functions defined by certain integral operator (English)
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    24 May 2007
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    Two function classes \({\mathcal T}Q(\alpha ,\beta ,\lambda )\) and \({\mathcal T}{\mathcal J}(\alpha ,\sigma )\) are introduced by defining these classes, respectively, in terms of the functions \(F(z) = Q_\beta ^\alpha f(z)\) and \(F(z) = J_\alpha f(z),\) involving certain integral operators and satisfying the inequality: \[ \left| {\frac{{z\left( {F(Z)} \right)^\prime }}{{F(Z)}} - 1} \right| \leq \text{Re} \left\{ {\frac{{z\left( {F(Z)} \right)^\prime }}{{F(Z)}}} \right\} - \sigma \quad (z \in D), \] where \(\alpha>0, \beta>-1\: \text{and} \: 0\leq\sigma\leq1,\) D is the open unit disk, and \( f(z) = z - \sum_{n = 2}^\infty {a_n z^n }.\) The coefficient inequalities for the function \(f(z)\) belonging to the above classes (which are of uniformly starlike type) are obtained, and also similar investigations are undertaken for the functions which are of uniformly convex type.
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    analytic and univalent functions
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    integral operator
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    uniformly starlike functions
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    uniformly convex functions
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