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星像的典型实照函数
TYPICALLY REAL FUNCTIONS HAVING STARLIKE IMAGES
【摘要】 <正> 称这处函数 f(z)为单位圆上的一个典型实照函数,记其全体为 T_r.设 f(z)是 T_r中的一个函数,f(z)映照|z|<的像是区域 D,如果对于 D 中任意一点都可以用完全落在 D 中的直线段与ω=0相联结的话,称 f(z)是一個星像的典型实照
【Abstract】 Let the function(?)with real coefficients αυ(κ)be regular in |z|<1,and be such that fκ(z)mapsthe circle |z|=γ into α contour which passess through the real axles in exactly2κ points for every γ in the interval(?).Denote thefamily of all such functions by Тγκ,and write Тγ for Тγ1.Any function fκ(z)of the subclass Tγκ of Tγκ,if is such that for each γ in 1-δ<γ<1,the radius vector(?)turns continuously in the counterclockwise direction and makes κ complete revolutions as θ varies from 0 to 2π.We prove in the present note that any fκ(z)of Tγκ can be represented inthe form(?)with an increasing function α(θ)satisfying(?).By means of thisformula,we establish the following:Theorem.If fκ(z)∈Τγκ,then(?)All these estimates are precise.A function(?),with real coeffi-cients is said to be belonging to the subclass Tγκ(ρ,р),if there exists αρ(0<<ρ<1)such that(?)The coefficients of such a function fκ,р(z)satisfy the inequality(?)This estimate is precise.The result holds good even when ακ+рn(κ)(ρ,р)are notall real,if fκ,р(z)is κ-valent and(?)
- 【文献出处】 数学学报 ,Acta Mathematica Sinica , 编辑部邮箱 ,1958年01期
- 【被引频次】1
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