Logarithmic derivative estimates of meromorphic functions of finite order in the half-plane-Reference-Cited by-同舟云学术

Logarithmic derivative estimates of meromorphic functions of finite order in the half-plane

Published:2020-12-25 Issue:2 Volume:54 Page:172-187
ISSN:2411-0620
Container-title:Matematychni Studii
language:
Short-container-title:Mat. Stud.

Author:

Chyzhykov I.E.,Mokhon'ko A.Z.

Abstract

We established new sharp estimates outside exceptional sets for of the logarithmic derivatives $\frac{d^ {k} \log f(z)}{dz^k}$ and its generalization $\frac{f^{(k)}(z)}{f^{(j)}(z)}$, where $f$ is a meromorphic function $f$ in the upper half-plane, $k>j\ge0$ are integers. These estimates improve known estimates due to the second author in the class of meromorphic functions of finite order.Examples show that size of exceptional sets are best possible in some sense.

Publisher

Ivan Franko National University of Lviv

Subject

General Mathematics

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