Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc

In the case of the complex plane, it is known that there exists a finite set of rational numbers containing all possible growth orders of solutions of f(k)+ak-1(z)f(k-1)+⋯+a1(z)f′+a0(z)f=0 with polynomial coefficients. In the present paper, it is shown by an example that a unit disc counterpart of s...

Full description

Saved in:
Bibliographic Details
Main Authors: Martin Chuaqui, Janne Gröhn, Janne Heittokangas, Jouni Rättyä
Format: Article
Language:English
Published: Wiley 2011-01-01
Series:Abstract and Applied Analysis
Online Access:http://dx.doi.org/10.1155/2011/928194
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832554539966791680
author Martin Chuaqui
Janne Gröhn
Janne Heittokangas
Jouni Rättyä
author_facet Martin Chuaqui
Janne Gröhn
Janne Heittokangas
Jouni Rättyä
author_sort Martin Chuaqui
collection DOAJ
description In the case of the complex plane, it is known that there exists a finite set of rational numbers containing all possible growth orders of solutions of f(k)+ak-1(z)f(k-1)+⋯+a1(z)f′+a0(z)f=0 with polynomial coefficients. In the present paper, it is shown by an example that a unit disc counterpart of such finite set does not contain all possible T- and M-orders of solutions, with respect to Nevanlinna characteristic and maximum modulus, if the coefficients are analytic functions belonging either to weighted Bergman spaces or to weighted Hardy spaces. In contrast to a finite set, possible intervals for T- and M-orders are introduced to give detailed information about the growth of solutions. Finally, these findings yield sharp lower bounds for the sums of T- and M-orders of functions in the solution bases.
format Article
id doaj-art-02488ab3cedb4674a5dfa27a7e4da816
institution Kabale University
issn 1085-3375
1687-0409
language English
publishDate 2011-01-01
publisher Wiley
record_format Article
series Abstract and Applied Analysis
spelling doaj-art-02488ab3cedb4674a5dfa27a7e4da8162025-02-03T05:51:08ZengWileyAbstract and Applied Analysis1085-33751687-04092011-01-01201110.1155/2011/928194928194Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit DiscMartin Chuaqui0Janne Gröhn1Janne Heittokangas2Jouni Rättyä3Departamento de Matemáticas, Pontificia Universidad Católica de Chile, Casilla 306, Correo 22 Santiago, 6904411 Macual Santiago, ChileDepartment of Physics and Mathematics, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, FinlandDepartment of Physics and Mathematics, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, FinlandDepartment of Physics and Mathematics, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, FinlandIn the case of the complex plane, it is known that there exists a finite set of rational numbers containing all possible growth orders of solutions of f(k)+ak-1(z)f(k-1)+⋯+a1(z)f′+a0(z)f=0 with polynomial coefficients. In the present paper, it is shown by an example that a unit disc counterpart of such finite set does not contain all possible T- and M-orders of solutions, with respect to Nevanlinna characteristic and maximum modulus, if the coefficients are analytic functions belonging either to weighted Bergman spaces or to weighted Hardy spaces. In contrast to a finite set, possible intervals for T- and M-orders are introduced to give detailed information about the growth of solutions. Finally, these findings yield sharp lower bounds for the sums of T- and M-orders of functions in the solution bases.http://dx.doi.org/10.1155/2011/928194
spellingShingle Martin Chuaqui
Janne Gröhn
Janne Heittokangas
Jouni Rättyä
Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
Abstract and Applied Analysis
title Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
title_full Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
title_fullStr Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
title_full_unstemmed Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
title_short Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
title_sort possible intervals for t and m orders of solutions of linear differential equations in the unit disc
url http://dx.doi.org/10.1155/2011/928194
work_keys_str_mv AT martinchuaqui possibleintervalsfortandmordersofsolutionsoflineardifferentialequationsintheunitdisc
AT jannegrohn possibleintervalsfortandmordersofsolutionsoflineardifferentialequationsintheunitdisc
AT janneheittokangas possibleintervalsfortandmordersofsolutionsoflineardifferentialequationsintheunitdisc
AT jounirattya possibleintervalsfortandmordersofsolutionsoflineardifferentialequationsintheunitdisc