UNT Theses and Dissertations - 472 Matching Results

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On Sets and Functions in a Metric Space

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.
Date: December 1971
Creator: Beeman, Anne L.
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On Sharp Permutation Groups whose Point Stabilizers are Certain Frobenius Groups

Description: We investigate non-geometric sharp permutation groups of type {0,k} whose point stabilizers are certain Frobenius groups. We show that if a point stabilizer has a cyclic Frobenius kernel whose order is a power of a prime and Frobenius complement cyclic of prime order, then the point stabilizer is isomorphic to the symmetric group on 3 letters, and there is up to permutation isomorphism, one such permutation group. Further, we determine a significant structural description of non-geometric sharpā€¦ more
Date: May 2023
Creator: Norman, Blake Addison
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On Steinhaus Sets, Orbit Trees and Universal Properties of Various Subgroups in the Permutation Group of Natural Numbers

Description: In the first chapter, we define Steinhaus set as a set that meets every isometric copy of another set at exactly one point. We show that there is no Steinhaus set for any four-point subset in a plane.In the second chapter, we define the orbit tree of a permutation group of natural numbers, and further introduce compressed orbit trees. We show that any rooted finite tree can be realized as a compressed orbit tree of some permutation group. In the third chapter, we investigate certain classes of ā€¦ more
Date: August 2012
Creator: Xuan, Mingzhi
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On the density of minimal free subflows of general symbolic flows.

Description: This paper studies symbolic dynamical systems {0, 1}G, where G is a countably infinite group, {0, 1}G has the product topology, and G acts on {0, 1}G by shifts. It is proven that for every countably infinite group G the union of the minimal free subflows of {0, 1}G is dense. In fact, a stronger result is obtained which states that if G is a countably infinite group and U is an open subset of {0, 1}G, then there is a collection of size continuum consisting of pairwise disjoint minimal free subflā€¦ more
Date: August 2009
Creator: Seward, Brandon Michael
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On the Descriptive Complexity and Ramsey Measure of Sets of Oracles Separating Common Complexity Classes

Description: As soon as Bennett and Gill first demonstrated that, relative to a randomly chosen oracle, P is not equal to NP with probability 1, the random oracle hypothesis began piquing the interest of mathematicians and computer scientists. This was quickly disproven in several ways, most famously in 1992 with the result that IP equals PSPACE, in spite of the classes being shown unequal with probability 1. Here, we propose what could be considered strengthening of the random oracle hypothesis, using a stā€¦ more
Date: August 2022
Creator: Creiner, Alex
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On the Development of Descriptive Set Theory

Description: In the thesis, the author traces the historical development of descriptive set theory from the work of H. Lebesgue to the introduction of projective descriptive set theory. Proofs of most of the major results are given. Topics covered include Corel lattices, universal sets, the operation A, analytic sets, coanalytic sets, and the continuum hypothesis The appendix contains a translation of the famous letters exchanged between R. Baire, E. Borel, J. Hadamard and H. Lebesgue concerning Zermelo's aā€¦ more
Date: August 1988
Creator: Schlee, Glen A. (Glen Alan)
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On the Existence and Uniqueness of Solutions of Two Differential Equations

Description: The purpose of this paper is to study two differential equations. A method of approximation by iteration is used to define sequences of functions which converge to solutions of these equations. Some properties of the solutions are proved for general boundary conditions and certain special solutions are studied in detail.
Date: August 1965
Creator: Keath, Mary Katherine
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On the Stielitjes Integral

Description: This paper is a study of the Stieltjes integral, a generalization of the Riemann integral normally studied in introductory calculus courses. The purpose of the paper is to investigate many of the basic manipulative properties of the integral.
Date: August 1972
Creator: Keagy, Thomas A.
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On the Subspace Dichotomy of Lp[0; 1] for 2 < p < āˆž

Description: The structure and geometry of subspaces of a given Banach space is among the most fundamental questions in Functional Analysis. In 1961, Kadec and Pelczyński pioneered a field of study by analyzing the structures of subspaces and basic sequences in L_p[0,1] under a naturally occurring restriction of p, 2 < p <\infty. They proved that any infinite-dimensional subspace X\subset L_p[0,1] for 2<p<\infty must either be isomorphic to l_2 and complemented in L_p or must contain a complemented subspaceā€¦ more
Date: August 2021
Creator: James, Christopher W
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On Uniform Convergence

Description: In this paper, we will be concerned primarily with series of functions and a particular type of convergence which will be described. The purpose of this paper is to familiarize the reader with the concept of uniform convergence. In the main it is a compilation of material found in various references and revised to conform to standard notation.
Date: 1951
Creator: Drew, Dan Dale
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Operators on Continuous Function Spaces and Weak Precompactness

Description: If T:C(H,X)-->Y is a bounded linear operator then there exists a unique weakly regular finitely additive set function m:-->L(X,Y**) so that T(f) = āˆ«Hfdm. In this paper, bounded linear operators on C(H,X) are studied in terms the measure given by this representation theorem. The first chapter provides a brief history of representation theorems of these classes of operators. In the second chapter the represenation theorem used in the remainder of the paper is presented. If T is a weakly compact oā€¦ more
Date: August 1988
Creator: Abbott, Catherine Ann
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Optimal Look-Ahead Stopping Rules for Simple Random Walk

Description: In a stopping rule problem, a real-time player decides to stop or continue at stage n based on the observations up to that stage, but in a k-step look-ahead stopping rule problem, we suppose the player knows k steps ahead. The aim of this Ph.D. dissertation is to study this type of prophet problems for simple random walk, determine the optimal stopping rule and calculate the expected return for them. The optimal one-step look-ahead stopping rule for a finite simple random walk is determined in ā€¦ more
Date: August 2021
Creator: Sharif Kazemi, Zohreh
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Optimal Pair-Trading Decision Rules for a Class of Non-linear Boundary Crossings by Ornstein-Uhlenbeck Processes

Description: The most useful feature used in finance of the Ornstein-Uhlenbeck (OU) stochastic process is its mean-reverting property: the OU process tends to drift towards its long- term mean (its equilibrium state) over time. This important feature makes the OU process arguably the most popular statistical model for developing best pair-trading strategies. However, optimal strategies depend crucially on the first passage time (FPT) of the OU process to a suitably chosen boundary and its probability densiā€¦ more
Date: December 2021
Creator: Tamakloe, Emmanuel Edem Kwaku
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Optimal Strategies for Stopping Near the Top of a Sequence

Description: In Chapter 1 the classical secretary problem is introduced. Chapters 2 and 3 are variations of this problem. Chapter 2, discusses the problem of maximizing the probability of stopping with one of the two highest values in a Bernoulli random walk with arbitrary parameter p and finite time horizon n. The optimal strategy (continue or stop) depends on a sequence of threshold values (critical probabilities) which has an oscillating pattern. Several properties of this sequence have been proved by Drā€¦ more
Date: December 2015
Creator: Islas Anguiano, Jose Angel
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Option Pricing Under New Classes of Jump-Diffusion Processes

Description: In this dissertation, we introduce novel exponential jump-diffusion models for pricing options. Firstly, the normal convolution gamma mixture jump-diffusion model is presented. This model generalizes Merton's jump-diffusion and Kou's double exponential jump-diffusion. We show that the normal convolution gamma mixture jump-diffusion model captures some economically important features of the asset price, and that it exhibits heavier tails than both Merton jump-diffusion and double exponential jumā€¦ more
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Date: December 2023
Creator: Adiele, Ugochukwu Oliver
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Orthogonal Functions

Description: In this study the idea of orthogonality of two lines will be generalized to the idea of orthogonality of two functions. In particular, the orthogonality of two lines may be treated from the standpoint of the orthogonality of two vectors in two-dimensional space.
Date: 1956
Creator: Harrison, Ivan
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Overrings of an Integral Domain

Description: This dissertation focuses on the properties of a domain which has the property that each ideal is a finite intersection of a Ļ€-ideal, the properties of a domain which have the property that each ideal is a finite product of Ļ€-ideal, and the containment relations of the resulting classes of ideals. Chapter 1 states definitions which are needed in later chapters. Chapters 2 and 3 focuses on domains which have the property that each ideal in D is a finite intersection of Ļ€-ideals while Chapter 4 fā€¦ more
Date: August 1992
Creator: Emerson, Sharon Sue
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A Partial Characterization of Upper Semi-Continuous Decompositions

Description: The goal of this paper is to characterize, at least partially, upper semi-continuous decompositions of topological spaces and the role that upper semi-continuity plays in preserving certain topological properties under decomposition mappings. Attention is also given to establishing what role upper semi-continuity plays in determining conditions under which decomposition spaces possess certain properties. A number of results for non-upper semi-continuous decompositions are included to help clariā€¦ more
Date: December 1973
Creator: Dennis, William Albert
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Partially Ordered Groups and Rings

Description: This report presents both the most essential known results and new results in the theory of partially ordered groups and rings. This report deals with partially ordered groups and rings in an algebraic aspect because it is more important than partially ordered, fully ordered and lattice-ordered semigroup theory.
Date: August 1968
Creator: Lott, Kenneth L.
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Partition Properties for Non-Ordinal Sets under the Axiom of Determinacy

Description: In this paper we explore coloring theorems for the reals, its quotients, cardinals, and their combinations. This work is done under the scope of the axiom of determinacy. We also explore generalizations of Mycielski's theorem and show how these can be used to establish coloring theorems. To finish, we discuss the strange realm of long unions.
Date: May 2017
Creator: Holshouser, Jared
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