Estimates from below for characteristic functions of probability laws

Let $varphi$ be the characteristic function of a probabilitylaw F that is analytic in $mathbb{D}_{R}={zcolon |z|<R},$ $0<Rleq+infty,$ $M(r,varphi)=maxleft{|varphi(z)|colon|z|=r<Right}$ and $W_{F}(x)=1-F(x)+F(-x),$ $xgeq 0.$ Aconnection between the growth of $M(r,varphi)$ and thedecrease it...

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Bibliographic Details
Main Authors: M. I. Parolya, M. M. Sheremeta
Format: Article
Language:German
Published: Ivan Franko National University of Lviv 2013-04-01
Series:Математичні Студії
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Online Access:http://matstud.org.ua/texts/2013/39_1/54-66.pdf
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Summary:Let $varphi$ be the characteristic function of a probabilitylaw F that is analytic in $mathbb{D}_{R}={zcolon |z|<R},$ $0<Rleq+infty,$ $M(r,varphi)=maxleft{|varphi(z)|colon|z|=r<Right}$ and $W_{F}(x)=1-F(x)+F(-x),$ $xgeq 0.$ Aconnection between the growth of $M(r,varphi)$ and thedecrease it of $W_{F}(x)$ is investigated in terms of estimatesfrom below. For entire characteristic functions {it} is proved,for example, that if $ln x_kgeqlambdaln(frac{1}{x_k}lnfrac{1}{W_{F}(x_k)})$ for someincreasing sequence $(x_k)$ such that $x_{k+1}=O(x_k),kightarrowinfty,$ then $lnfrac{ln M(r,varphi)}{r}geq(1+o(1))lambdaln r$ as $rightarrow+infty.$
ISSN:1027-4634