论文标题
SCHUR算法在某些分析功能的可变性区域的应用-II
An application of Schur algorithm to variability regions of certain analytic functions-II
论文作者
论文摘要
我们继续对\ cite {ali-vasudevarao-yanagihara-2018}中的可变性区域进行研究,其中作者确定了可变性区域$v_Ω^j(z_0,c)= \ {\ int_0^{\ int_0^{z__0} Z____0} z^} z^{j}(j}(z) - g(z) - g(z) - d z(g(0)) ω,\; (P^{-1} \circ g) (z) = c_0 +c_1z + \cdots + c_n z^n + \cdots \}$ for each fixed $z_0 \in {\mathbb D}$, $j=-1,0,1,2, \ldots$ and $c = (c_0, c_1 , \ldots , c_n) \in \ Mathbb {C}^{n+1} $,当$ω\ subsetNeq \ mathbb {c} $是一个凸域,而$ p $是单位磁盘$ {\ mathbb d} $ to $ω$的单位磁盘$ {\ mathbb d} $的保形映射。在本文中,我们首先表明,在$ n = 0 $,$ j = -1 $和$ c = 0 $的情况下,在\ cite {ali-vasudevarao-yanagihara-2018}中获得的结果仍然存在时,只有一个人假设$ω$与$ p(0)$相关。令$ {cv}(ω)$是$ {\ Mathbb d} $中的分析函数$ f $的类别,$ f(0)= f'(0)= f'(0)-1 = 0 $满足$ 1+zf''(z)/f'(z)/f'(z)/f'(z)\ inω$。作为应用程序,我们确定$ \ log f'(z_0)$的可变性区域时,$ f $范围超过$ \ mathcal {cv}(ω)$,无论有或没有条件,$ f''(0)=λ$和$ f'''(0)=μ$。在这里,$λ$和$μ$是任意定位的值。通过选择特定的$ω$,我们获得了其他众所周知的分析和单价功能子类的$ \ log f'(z_0)$的精确可变性区域。
We continue our study on variability regions in \cite{Ali-Vasudevarao-Yanagihara-2018}, where the authors determined the region of variability $V_Ω^j (z_0, c ) = \{ \int_0^{z_0} z^{j}(g(z)-g(0))\, d z : g({\mathbb D}) \subset Ω, \; (P^{-1} \circ g) (z) = c_0 +c_1z + \cdots + c_n z^n + \cdots \}$ for each fixed $z_0 \in {\mathbb D}$, $j=-1,0,1,2, \ldots$ and $c = (c_0, c_1 , \ldots , c_n) \in \mathbb{C}^{n+1}$, when $Ω\subsetneq\mathbb{C}$ is a convex domain, and $P$ is a conformal map of the unit disk ${\mathbb D}$ onto $Ω$. In the present article, we first show that in the case $n=0$, $j=-1$ and $c=0$, the result obtained in \cite{Ali-Vasudevarao-Yanagihara-2018} still holds when one assumes only that $Ω$ is starlike with respect to $P(0)$. Let $\mathcal{CV}(Ω)$ be the class of analytic functions $f$ in ${\mathbb D}$ with $f(0)=f'(0)-1=0$ satisfying $1+zf''(z)/f'(z) \in Ω$. As applications we determine variability regions of $\log f'(z_0)$ when $f$ ranges over $\mathcal{CV}(Ω)$ with or without the conditions $f''(0)= λ$ and $f'''(0)= μ$. Here $λ$ and $μ$ are arbitrarily preassigned values. By choosing particular $Ω$, we obtain the precise variability regions of $\log f'(z_0)$ for other well-known subclasses of analytic and univalent functions.