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**Degree Discipline:**Mathematics

**Collection:**UNT Theses and Dissertations

### Complemented Subspaces of Bounded Linear Operators

**Date:**August 2003

**Creator:**Bahreini Esfahani, Manijeh

**Description:**For many years mathematicians have been interested in the problem of whether an operator ideal is complemented in the space of all bounded linear operators. In this dissertation the complementation of various classes of operators in the space of all bounded linear operators is considered. This paper begins with a preliminary discussion of linear bounded operators as well as operator ideals. Let L(X, Y ) be a Banach space of all bounded linear operator between Banach spaces X and Y , K(X, Y ) be the space of all compact operators, and W(X, Y ) be the space of all weakly compact operators. We denote space all operator ideals by O.

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### Level Curves of the Angle Function of a Positive Definite Symmetric Matrix

**Access:**Use of this item is restricted to the UNT Community.

**Date:**December 2009

**Creator:**Bajracharya, Neeraj

**Description:**Given a real N by N matrix A, write p(A) for the maximum angle by which A rotates any unit vector. Suppose that A and B are positive definite symmetric (PDS) N by N matrices. Then their Jordan product {A, B} := AB + BA is also symmetric, but not necessarily positive definite. If p(A) + p(B) is obtuse, then there exists a special orthogonal matrix S such that {A, SBS^(-1)} is indefinite. Of course, if A and B commute, then {A, B} is positive definite. Our work grows from the following question: if A and B are commuting positive definite symmetric matrices such that p(A) + p(B) is obtuse, what is the minimal p(S) such that {A, SBS^(-1)} indefinite? In this dissertation we will describe the level curves of the angle function mapping a unit vector x to the angle between x and Ax for a 3 by 3 PDS matrix A, and discuss their interaction with those of a second such matrix.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc28376/

### Near-Rings

**Date:**May 1972

**Creator:**Baker, Edmond L.

**Description:**The primary objective of this work is to discuss some of the elementary properties of near-rings as they are related to rings. This study is divided into three subdivisions: (1) Basic Properties and Concepts of Near-Rings; (2) The Ideal Structure of Near-Rings; and (3) Homomorphism and Isomorphism of Near-Rings.

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### Completely Simple Semigroups

**Date:**August 1968

**Creator:**Barker, Bruce W.

**Description:**The purpose of this thesis is to explore some of the characteristics of 0-simple semigroups and completely 0-simple semigroups.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130974/

### T-Functions

**Date:**June 1960

**Creator:**Barlow, John Rice

**Description:**The main purpose of this paper is to make a detailed study of a certain class T of complex functions. The functions of the class T have a special mapping property and are meromorphic in every region. As an application of this study, certain elementary functions are defined and studied in terms of a special T-function.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc108077/

### Product and Function Spaces

**Date:**August 1971

**Creator:**Barrett, Lewis Elder

**Description:**In this paper the Cartesian product topology for an arbitrary family of topological spaces and some of its basic properties are defined. The space is investigated to determine which of the separation properties of the component spaces are invariant.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131391/

### Properties of Order Relations and Certain Partly Ordered Systems

**Date:**June 1961

**Creator:**Barros, David Nicholas

**Description:**The purpose of this paper is to present a study of partly ordered sets. It includes a rigorous development of relations based on the notion of a relation as a set, lattices, and theorems concerning the lattice of subgroups of a group.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc108130/

### Mycielski-Regular Measures

**Date:**August 2011

**Creator:**Bass, Jeremiah Joseph

**Description:**Let μ be a Radon probability measure on M, the d-dimensional Real Euclidean space (where d is a positive integer), and f a measurable function. Let P be the space of sequences whose coordinates are elements in M. Then, for any point x in M, define a function ƒn on M and P that looks at the first n terms of an element of P and evaluates f at the first of those n terms that minimizes the distance to x in M. The measures for which such sequences converge in measure to f for almost every sequence are called Mycielski-regular. We show that the self-similar measure generated by a finite family of contracting similitudes and which up to a constant is the Hausdorff measure in its dimension on an invariant set C is Mycielski-regular.

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### A Set of Axioms for a Topological Space

**Date:**August 1960

**Creator:**Batcha, Joseph Patrick

**Description:**Axioms for a topological space are generally based on neighborhoods where "neighborhood" is an undefined term. Then, limit points are defined in terms of neighborhoods. However, limit points seem to be the basic concept of a topological space, rather than neighborhoods. For this reason, it will be attempted to state a set of axioms for a topological space, using limit point as the undefined concept, and to delete the idea of neighborhoods from the theory.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc108089/

### The Development of the Natural Numbers by Means of the Peano Postulates

**Date:**1951

**Creator:**Baugh, Orvil Lee

**Description:**This thesis covers the development of the natural numbers by means of the peano postulates.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc96984/

### On Sets and Functions in a Metric Space

**Date:**December 1971

**Creator:**Beeman, Anne L.

**Description:**The purpose of this thesis is to study some of the properties of metric spaces. An effort is made to show that many of the properties of a metric space are generalized properties of R, the set of real numbers, or Euclidean n--space, and are specific cases of the properties of a general topological space.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131457/

### Lebesgue Linear Measure

**Date:**1940

**Creator:**Beeman, William Edwin

**Description:**This paper discusses the concept of a general definition of measure, and shows that the Lebesgue measure satisfies the requirements set forth for the ideal definition.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc75587/

### Compactness and Equivalent Notions

**Date:**August 1967

**Creator:**Bell, Wayne Charles

**Description:**One of the classic theorems concerning the real numbers states that every open cover of a closed and bounded subset of the real line contains a finite subcover. Compactness is an abstraction of that notion, and there are several ideas concerning it which are equivalent and many which are similar. The purpose of this paper is to synthesize the more important of these ideas. This synthesis is accomplished by demonstrating either situations in which two ordinarily different conditions are equivalent or combinations of two or more properties which will guarantee a third.

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### Restricting Invariants and Arrangements of Finite Complex Reflection Groups

**Date:**August 2015

**Creator:**Berardinelli, Angela

**Description:**Suppose that G is a finite, unitary reflection group acting on a complex vector space V and X is a subspace of V. Define N to be the setwise stabilizer of X in G, Z to be the pointwise stabilizer, and C=N/Z. Then restriction defines a homomorphism from the algebra of G-invariant polynomial functions on V to the algebra of C-invariant functions on X. In my thesis, I extend earlier work by Douglass and Röhrle for Coxeter groups to the case where G is a complex reflection group of type G(r,p,n) in the notation of Shephard and Todd and X is in the lattice of the reflection arrangement of G. The main result characterizes when the restriction mapping is surjective in terms of the exponents of G and C and their reflection arrangements.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc804919/

### Dimensions in Random Constructions.

**Date:**May 2002

**Creator:**Berlinkov, Artemi

**Description:**We consider random fractals generated by random recursive constructions, prove zero-one laws concerning their dimensions and find their packing and Minkowski dimensions. Also we investigate the packing measure in corresponding dimension. For a class of random distribution functions we prove that their packing and Hausdorff dimensions coincide.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc3160/

### Some Theorems and Product Spaces

**Date:**1957

**Creator:**Bethel, Edward Lee

**Description:**This thesis is a study of some axioms and theorems, and product spaces.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc107937/

### Metric Spaces

**Date:**1957

**Creator:**Bilyeu, Russell Gene

**Description:**This thesis covers fundamental properties of metric spaces, as well as completeness, compactness, and separability of metric spaces.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc107938/

### Algebraic Integers

**Date:**August 1969

**Creator:**Black, Alvin M.

**Description:**The primary purpose of this thesis is to give a substantial generalization of the set of integers Z, where particular emphasis is given to number theoretic questions such as that of unique factorization. The origin of the thesis came from a study of a special case of generalized integers called the Gaussian Integers, namely the set of all complex numbers in the form n + mi, for m,n in Z. The main generalization involves what are called algebraic integers.

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### Means and Mean Value Theorems

**Date:**1951

**Creator:**Blummer, Raymond O.

**Description:**This study covers means, mean value theorems of the differential calculus, and mean value theorems of integral calculus.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc96987/

### Random Sampling

**Date:**January 1957

**Creator:**Booker, Aaron Hicks

**Description:**The purpose of this study is to show the use of random sampling in solving certain mathematical problems. The origin of random numbers to be used in sampling is discussed and methods of sampling from known distributions are then given together with an indication that the sampling procedures are unbiased.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130442/

### The Riemann-Complete Integral

**Date:**May 1972

**Creator:**Boyd, Eddie

**Description:**The problem with which this paper is concerned is that of defining the Riemann-Complete Integral and comparing it with the Riemann and the Lebesgue Integrals.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131504/

### Some Results of Two Topological Spaces

**Date:**August 1955

**Creator:**Boyd, James Robert

**Description:**This thesis explores some results of two topological spaces.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130437/

### The Study of Translation Equivalence on Integer Lattices

**Date:**August 2003

**Creator:**Boykin, Charles Martin

**Description:**This paper is a contribution to the study of countable Borel equivalence relations on standard Borel spaces. We concentrate here on the study of the nature of translation equivalence. We study these known hyperfinite spaces in order to gain insight into the approach necessary to classify certain variables as either being hyperfinite or not. In Chapter 1, we will give the basic definitions and examples of spaces used in this work. The general construction of marker sets is developed in this work. These marker sets are used to develop several invariant tilings of the equivalence classes of specific variables . Some properties that are equivalent to hyperfiniteness in the certain space are also developed. Lastly, we will give the new result that there is a continuous injective embedding from certain defined variables.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc4345/

### Weakly Dense Subsets of Homogeneous Complete Boolean Algebras

**Date:**August 1990

**Creator:**Bozeman, Alan Kyle

**Description:**The primary result from this dissertation is following inequality: d(B) ≤ min(2^< wd(B),sup{λ^c(B): λ < wd(B)}) in ZFC, where B is a homogeneous complete Boolean algebra, d(B) is the density, wd(B) is the weak density, and c(B) is the cellularity of B. Chapter II of this dissertation is a general overview of homogeneous complete Boolean algebras. Assuming the existence of a weakly inaccessible cardinal, we give an example of a homogeneous complete Boolean algebra which does not attain its cellularity. In chapter III, we prove that for any integer n > 1, wd_2(B) = wd_n(B). Also in this chapter, we show that if X⊂B is κ—weakly dense for 1 < κ < sat(B), then sup{wd_κ(B):κ < sat(B)} = d(B). In chapter IV, we address the following question: If X is weakly dense in a homogeneous complete Boolean algebra B, does there necessarily exist b € B\{0} such that {x∗b: x ∈ X} is dense in B|b = {c € B: c ≤ b}? We show that the answer is no for collapsing algebras. In chapter V, we give new proofs to some well known results concerning supporting antichains. A direct consequence of these results is the relation c(B) < wd(B), ...

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc330803/