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Sharp starlikeness conditions for analytic functions with bounded derivative

Published online by Cambridge University Press:  09 April 2009

Frode Rønning
Affiliation:
Sør Trøndelag College School of Teacher EducationN-7004 TrondheimNorway e-mail: [email protected]
Stephan Ruscheweyh
Affiliation:
Mathematisches Institut Universität WürzburgD-97074 WürzburgGermany e-mail: [email protected]
Nikolas Samaris
Affiliation:
Department of Mathematics University of PatrasGR-26500 PatrasGreece e-mail: [email protected]
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Abstract

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We develop sharp conditions for various types of starlikeness for functions analytic in the unit disk with bounded derivatives. We also describe the precise range {zf′(z)/f(z): z ∈ D, f}, where f means f (0) = 0, f′(0) = 1, and |f′(z) - 1 |< ≦ λ in the unit disc D, and draw some cnoslusions from that.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 2000

References

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