Department

Mathematics

Document Type

Article

Publication Source

International Journal of Mathematics and Mathematical Sciences

Publication Date

1996-01-01

Volume

19

Issue

4

First Page

789

Last Page

795

Abstract

We study the problem maxh∊Sℜ[h(z1) + h(z2)] with z1, z2 in Δ. We show that no rotation of the Koebe function is a solution for this problem except possibly its real rotation, and only when [formula omitted] or z1, z2 are both real, and are in a neighborhood of the x-axis. We prove that if the omitted set of the extremal function f is part of a straight line that passes through f(z1) or f(z2) then f is the Koebe function or its real rotation. We also show the existence of solutions that are not unique and are different from the Koebe function or its real rotation. The situation where the extremal value is equal to zero can occur and it is proved, in this case, that the Koebe function is a solution if and only if z1 and z2 are both real numbers and z1z2 < 0. © 1996, Hindawi Publishing Corporation. All rights reserved.

Keywords

Quadratic Differential, Support Points, Univalent Functions

DOI

10.1155/S0161171296001093

Comments

© 1996 Hindawi Publishing Corporation.

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

https://doi.org/10.1155/S0161171296001093

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