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Abstract Header
Universal Composition Operators on the Hardy Space with Linear Fractional Symbols
Author Info
Hassan, Aiham A
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1687181576013619
Abstract Details
Year and Degree
2023, Doctor of Philosophy (Ph.D.), Bowling Green State University, Mathematics.
Abstract
In this dissertation, we study universality of linear fractional composition operators on the Fréchet spaces
H(𝔻)
of holomorphic functions on the open unit disk
𝔻
and on the Hardy space
H
2
. By definition, a sequence of operators
T
n
is universal if there is a vector
x
such that the sequence {
x
,
T
1
x
,
T
2
x
, …} is dense in the space. Specifically, we obtain necessary conditions and sufficient conditions for a sequence of composition operators
C
ϕ
n
:
H
2
→
H
2
to be universal on the Hardy space
H
2
with linear fractional symbols
ϕ
n
(
z
) = (
a
n
z+b
n
)/(
c
n
z+d
n
)
taking the open unit disk
𝔻
into itself, where
a
n
d
n
-b
n
c
n
= 1
. We show that if
C
ϕ
n
is universal and the sequence
d
n
/c
n
is bounded, then there is a subsequence
ϕ
n
k
for which the sequences of coefficients,
|a
n
k
|
,
|b
n
k
|
,
|c
n
k
|
,
|d
n
k
|
go to ∞, as
k → ∞
. In addition, the sequence
|a
n
k
| - |c
n
k
|
goes to 0. Furthermore, we also provide sufficient conditions for
C
ϕ
n
to be universal, in terms of the coefficients of
ϕ
n
. Lastly, in the special case when
ϕ
n
are automorphisms of the disk
𝔻
, we show that
C
ϕ
n
:
H
2
→
H
2
is universal on the Hardy space
H
2
if and only if the corresponding sequence
C
ϕ
n
:
H(𝔻)
→
H(𝔻)
is universal on the Fréchet spaces
H(𝔻)
Committee
Kit Chan, PhD (Committee Chair)
Apollos Nwauwa, PhD (Other)
Juan Bes, PhD (Committee Member)
So-Hsiang Chou, PhD (Committee Member)
Pages
81 p.
Subject Headings
Mathematics
Keywords
Hypercyclicity
;
Universal
;
Composition Operators
;
Hardy Space
;
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Hassan, A. A. (2023).
Universal Composition Operators on the Hardy Space with Linear Fractional Symbols
[Doctoral dissertation, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1687181576013619
APA Style (7th edition)
Hassan, Aiham.
Universal Composition Operators on the Hardy Space with Linear Fractional Symbols.
2023. Bowling Green State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1687181576013619.
MLA Style (8th edition)
Hassan, Aiham. "Universal Composition Operators on the Hardy Space with Linear Fractional Symbols." Doctoral dissertation, Bowling Green State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1687181576013619
Chicago Manual of Style (17th edition)
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Document number:
bgsu1687181576013619
Download Count:
39
Copyright Info
© 2023, all rights reserved.
This open access ETD is published by Bowling Green State University and OhioLINK.