On zeros of components of analytic curves and of derivatives of analytic functions

Author
M.M.Sheremeta, Yu.S.Trukhan
Lviv Ivan Franko National University
Abstract
For an analytic curve $F=(f_1, f_2, \dots, f_m), m\ge 1,$ in a domain $G$, let $d_F(z)$ be the radius of the largest disk centered at $z\in G$ in which any $f_j$ does not vanish. Lower estimates for $\sup\{d_F(z)\colon z\in G\}$ and $\sup\{d_F(z)l(|z|)\colon z\in G\}$ ($l$ be a positive continuous increasing to $+\infty$ function) are given. The cases $G=\mathbb C$ and $G=\{z\colon |z|<1\}$ are investigated.
Keywords
analytic curve, lower estimates, radius of unvanishing
DOI
doi:10.30970/ms.34.2.174-179
Reference
1. Bordulyak M.T., Sheremeta M.M., Trukhan Yu.S. On zeros of derivatives of an entire function// Mat. Stud. -- 2006. -- V.25, № 2. -- P.141--148.

2. Goldberg A.A., Ostrovsky I.V. Value distribution of meromorphic functions. -- AMS, 2008. -- 488 p.

3. Гольдберг А.А. О распределение значений $\sigma$--функции Вейерштрасса // Изв. вузов. Матем. -- 1966. -- \No 1. -- C. 43--46.

Pages
174-179
Volume
34
Issue
2
Year
2010
Journal
Matematychni Studii
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