On growth order of solutions of differential equations in a neighborhood of a branch point

Let $M_k$ be {the} set of $k$-valued meromorphic in$G={zcolon r_0leqslant |z|}$ functions with {a}~branch point of order$k-1$ {at} $infty$; let $E_ast$ be a set of circles {with finite} sum of radii. Denote$M_ast(r,f)=max|f(z)|, zin{te^{iheta}colon 0leqslanthetaleqslant2kpi,_0leqslant tleqslant r}s...

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Main Authors: A. Z. Mokhonko, A. A. Mokhonko
Format: Article
Language:deu
Published: Ivan Franko National University of Lviv 2013-10-01
Series:Математичні Студії
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Online Access:http://matstud.org.ua/texts/2013/40_1/53-65.pdf
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author A. Z. Mokhonko
A. A. Mokhonko
author_facet A. Z. Mokhonko
A. A. Mokhonko
author_sort A. Z. Mokhonko
collection DOAJ
description Let $M_k$ be {the} set of $k$-valued meromorphic in$G={zcolon r_0leqslant |z|}$ functions with {a}~branch point of order$k-1$ {at} $infty$; let $E_ast$ be a set of circles {with finite} sum of radii. Denote$M_ast(r,f)=max|f(z)|, zin{te^{iheta}colon 0leqslanthetaleqslant2kpi,_0leqslant tleqslant r}setminus E_ast, f!in! M_k;$$m(r,f)=frac{1}{2pi k}int_0^{2pik}!ln^+!|f(re^{iheta})|dheta$. If $fin M_k$ is a solution of the equation$P(z,f,f')=0$ and $P$ is a polynomial in all variables theneither $|f(re^{iheta})|<r^u,$ $re^{iheta}in GsetminusE_ast, u>0$ or $m(r,f)$ has growth order$hogeqslantfrac{1}{2k}$, and the following equality holds $lnM_ast(r,f)=(c+o(1))r^ho,$ $ceq0,$ $ro+infty.$
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spelling doaj-art-9cdffb3619db407ba5fb64cc433fa1512025-08-20T02:52:09ZdeuIvan Franko National University of LvivМатематичні Студії1027-46342013-10-014015365On growth order of solutions of differential equations in a neighborhood of a branch pointA. Z. MokhonkoA. A. MokhonkoLet $M_k$ be {the} set of $k$-valued meromorphic in$G={zcolon r_0leqslant |z|}$ functions with {a}~branch point of order$k-1$ {at} $infty$; let $E_ast$ be a set of circles {with finite} sum of radii. Denote$M_ast(r,f)=max|f(z)|, zin{te^{iheta}colon 0leqslanthetaleqslant2kpi,_0leqslant tleqslant r}setminus E_ast, f!in! M_k;$$m(r,f)=frac{1}{2pi k}int_0^{2pik}!ln^+!|f(re^{iheta})|dheta$. If $fin M_k$ is a solution of the equation$P(z,f,f')=0$ and $P$ is a polynomial in all variables theneither $|f(re^{iheta})|<r^u,$ $re^{iheta}in GsetminusE_ast, u>0$ or $m(r,f)$ has growth order$hogeqslantfrac{1}{2k}$, and the following equality holds $lnM_ast(r,f)=(c+o(1))r^ho,$ $ceq0,$ $ro+infty.$http://matstud.org.ua/texts/2013/40_1/53-65.pdfalgebraic differential equationbranch point of analytic functionmeromorphic solutionorder of growth
spellingShingle A. Z. Mokhonko
A. A. Mokhonko
On growth order of solutions of differential equations in a neighborhood of a branch point
Математичні Студії
algebraic differential equation
branch point of analytic function
meromorphic solution
order of growth
title On growth order of solutions of differential equations in a neighborhood of a branch point
title_full On growth order of solutions of differential equations in a neighborhood of a branch point
title_fullStr On growth order of solutions of differential equations in a neighborhood of a branch point
title_full_unstemmed On growth order of solutions of differential equations in a neighborhood of a branch point
title_short On growth order of solutions of differential equations in a neighborhood of a branch point
title_sort on growth order of solutions of differential equations in a neighborhood of a branch point
topic algebraic differential equation
branch point of analytic function
meromorphic solution
order of growth
url http://matstud.org.ua/texts/2013/40_1/53-65.pdf
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