University of Illinois Urbana-Champaign

Efficient quotient representation of meromorphic functions

Hopkins, Kevin Walter

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https://hdl.handle.net/2142/21400

Description

Title
Efficient quotient representation of meromorphic functions
Author(s)
Hopkins, Kevin Walter
Issue Date
1989
Doctoral Committee Chair(s)
Kaufman, Robert
Department of Study
Mathematics
Discipline
Mathematics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Mathematics
Language
eng
Abstract
  • Representations of meromorphic functions as quotients of analytic functions have been studied for years. Miles showed that any meromorphic function f can be written as f$\sb1$/f$\sb2$ where each f$\sb{\rm j}$ is entire and T(r,f$\sb{\rm j}$) $\leq$ AT(Br,f). This result is trivial if the pole set Z is finite. For an infinite pole set Z of f, he established the existence of entire f$\sb{\rm j}$ such that T(r,f$\sb{\rm j}$) $\leq$ A$\sp\prime$N(B$\sp\prime$r,Z).
  • Miles's technique, called balancing, was to add elements to the pole set Z in such a way that he could apply a result of Rubel and Taylor. Our technique is to add elements Z$\sp\prime$ and Z$\sp{\prime\prime}$ to the pole set Z in such a manner as to make the Fourier coefficients of $\rm\log\ \vert f\sb2(re\sp{i\theta})\vert$ small. We need to ensure that the number of zeros added in the balancing does not make N(r, Z $\cup$ Z$\sp\prime$ $\cup$ Z$\sp{\prime\prime}$) $\gg$ N(r,Z). We also need to ensure that the zeros added to make one coefficient small do not adversely interact with other coefficients.
  • Miles exhibited a function where T(r,f$\sb{\rm j}$) $\leq$ AT(r,f) is not possible on some sequence of r's. In this thesis we examine the cases where we can set the constant B to equal one in Miles's result.
  • We are able to achieve A = 1 + o(1) and B = 1 on a sequence of r$\sb{\rm n}$'s. For a meromorphic function f of finite order we achieve$$\rm A = O(\rho\ \max\ \left\{1,{n(r,Z)\over N(r,Z)}\right\})$$with B = 1 on a set of r's of positive logarithmic density. For a meromorphic function f of infinite order we obtain a more complicated expression for A with B = 1 on a set of positive logarithmic density.
Type of Resource
text
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http://hdl.handle.net/2142/21400
Copyright and License Information
Copyright 1989 Hopkins, Kevin Walter

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Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Mathematics