"Radii of covering disks for locally univalent harmonic mappings" by Sergey Yu Graf, Saminathan Ponnusamy et al.
 

Radii of covering disks for locally univalent harmonic mappings

Article Type

Research Article

Publication Title

Monatshefte fur Mathematik

Abstract

For a univalent smooth mapping f of the unit disk D of complex plane onto the manifold f(D) , let df(z0) be the radius of the largest univalent disk on the manifold f(D) centered at f(z0) (| z0| < 1). The main aim of the present article is to investigate how the radius dh(z0) varies when the analytic function h is replaced by a sense-preserving harmonic function f= h+ g¯. The main result includes sharp upper and lower bounds for the quotient df(z0) / dh(z0) , especially, for a family of locally univalent Q-quasiconformal harmonic mappings f= h+ g¯ on | z| < 1. In addition, estimate on the radius of the disk of convexity of functions belonging to certain linear invariant families of locally univalent Q-quasiconformal harmonic mappings of order α is obtained.

First Page

527

Last Page

548

DOI

10.1007/s00605-016-0904-2

Publication Date

7-1-2016

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