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**Degree Discipline:**Mathematics

**Collection:**UNT Theses and Dissertations

### Dimension Theory

**Date:**August 1986

**Creator:**Frere, Scot M. (Scot Martin)

**Description:**This paper contains a discussion of topological dimension theory. Original proofs of theorems, as well as a presentation of theorems and proofs selected from Ryszard Engelking's Dimension Theory are contained within the body of this endeavor. Preliminary notation is introduced in Chapter I. Chapter II consists of the definition of and theorems relating to the small inductive dimension function Ind. Large inductive dimension is investigated in Chapter III. Chapter IV comprises the definition of covering dimension and theorems discussing the equivalence of the different dimension functions in certain topological settings. Arguments pertaining to the dimension o f Jn are also contained in Chapter IV.

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### 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/

### Direct Sums of Rings

**Date:**August 1966

**Creator:**Hughes, Dolin F.

**Description:**This paper consists of a study of the direct sum U of two rings S and T. Such a direct sum is defined as the set of all ordered pairs (s1, t1), where s1 is an arbitrary element in S and t1 is an arbitrary element in T.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130723/

### Divisibility in Abelian Groups

**Date:**August 1966

**Creator:**Huie, Douglas Lee

**Description:**This thesis describes properties of Abelian groups, and develops a study of the properties of divisibility in Abelian groups.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130724/

### Dually Semimodular Consistent Lattices

**Date:**May 1988

**Creator:**Gragg, Karen E. (Karen Elizabeth)

**Description:**A lattice L is said to be dually semimodular if for all elements a and b in L, a ∨ b covers b implies that a covers a ∧ b. L is consistent if for every join-irreducible j and every element x in L, the element x ∨ j is a join-irreducible in the upper interval [x,l]. In this paper, finite dually semimodular consistent lattices are investigated. Examples of these lattices are the lattices of subnormal subgroups of a finite group. In 1954, R. P. Dilworth proved that in a finite modular lattice, the number of elements covering exactly k elements is equal to the number of elements covered by exactly k elements. Here, it is established that if a finite dually semimodular consistent lattice has the same number of join-irreducibles as meet-irreducibles, then it is modular. Hence, a converse of Dilworth's theorem, in the case when k equals 1, is obtained for finite dually semimodular consistent lattices. Several combinatorial results are shown for finite consistent lattices similar to those already established for finite geometric lattices. The reach of an element x in a lattice L is the difference between the rank of x*, the join of x and all ...

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### Duals and Weak Completeness in Certain Sequence Spaces

**Date:**August 1980

**Creator:**Leavelle, Tommy L. (Tommy Lee)

**Description:**In this paper the weak completeness of certain sequence spaces is examined. In particular, we show that each of the sequence spaces c0 and 9, 1 < p < c, is a Banach space. A Riesz representation for the dual space of each of these sequence spaces is given. A Riesz representation theorem for Hilbert space is also proven. In the third chapter we conclude that any reflexive space is weakly (sequentially) complete. We give 01 as an example of a non-reflexive space that is weakly complete. Two examples, c0 and YJ, are given of spaces that fail to be weakly complete.

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### The Dyadic Operator Approach to a Study in Conics, with some Extensions to Higher Dimensions

**Date:**1940

**Creator:**Shawn, James Loyd

**Description:**The discovery of a new truth in the older fields of mathematics is a rare event. Here an investigator may hope at best to secure greater elegance in method or notation, or to extend known results by some process of generalization. It is our purpose to make a study of conic sections in the spirit of the above remark, using the symbolism developed by Josiah Williard Gibbs.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc75602/

### Dynamics of One-Dimensional Maps: Symbols, Uniqueness, and Dimension

**Date:**May 1988

**Creator:**Brucks, Karen M. (Karen Marie), 1957-

**Description:**This dissertation is a study of the dynamics of one-dimensional unimodal maps and is mainly concerned with those maps which are trapezoidal. The trapezoidal function, f_e, is defined for eΣ(0,1/2) by f_e(x)=x/e for xΣ[0,e], f_e(x)=1 for xΣ(e,1-e), and f_e(x)=(1-x)/e for xΣ[1-e,1]. We study the symbolic dynamics of the kneading sequences and relate them to the analytic dynamics of these maps. Chapter one is an overview of the present theory of Metropolis, Stein, and Stein (MSS). In Chapter two a formula is given that counts the number of MSS sequences of length n. Next, the number of distinct primitive colorings of n beads with two colors, as counted by Gilbert and Riordan, is shown to equal the number of MSS sequences of length n. An algorithm is given that produces a bisection between these two quantities for each n. Lastly, the number of negative orbits of size n for the function f(z)=z^2-2, as counted by P.J. Myrberg, is shown to equal the number of MSS sequences of length n. For an MSS sequence P, let H_ϖ(P) be the unique common extension of the harmonics of P. In Chapter three it is proved that there is exactly one J(P)Σ[0,1] such that the ...

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### Dynamics, Thermodynamic formalism and Perturbations of Transcendental Entire Functions of Finite Singular Type

**Date:**May 2005

**Creator:**Coiculescu, Ion

**Description:**In this dissertation, we study the dynamics, fractal geometry and the topology of the Julia set of functions in the family H which is a set in the class S, the Speiser class of entire transcendental functions which have only finitely many singular values. One can think of a function from H as a generalized expanding function from the cosh family. We shall build a version of thermodynamic formalism for functions in H and we shall show among others, the existence and uniqueness of a conformal measure. Then we prove a Bowen's type formula, i.e. we show that the Hausdorff dimension of the set of returning points, is the unique zero of the pressure function. We shall also study conjugacies in the family H, perturbation of functions in the family and related dynamical properties. We define Perron-Frobenius operators for some functions naturally associated with functions in the family H and then, using fundamental properties of these operators, we shall prove the important result that the Hausdorff dimension of the subset of returning points depends analytically on the parameter taken from a small open subset of the n-dimensional parameter space.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc4783/

### Electronic Analog Computer Study of Effects of Motor Velocity and Driving Voltage Limits upon Servomechanism Performance

**Date:**1956

**Creator:**Haynes, Joe Preston

**Description:**The object of this thesis is (1) to demonstrate the value of an electronic analog computer for the solution of non-linear ordinary differential equations particularly when a large family of solutions is required; and (2) to obtain as a by-product results of practical applicability to servomechanism selection and analysis.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc107908/

### The Elementary Transcendental Functions of a Complex Variable as Defined by Integration

**Date:**1940

**Creator:**Wilson, Carroll K.

**Description:**The object of this paper is to define the elementary transcendental functions of a complex variable by means of integrals, and to discuss their properties.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc70281/

### Elements of Boolean Algebra Theory

**Date:**1957

**Creator:**Harvill, John Bowman

**Description:**The primary purpose of this paper is to state a set of postulates for Boolean algebra and show the characteristic theorems derivable from them, and to unify in one paper the more important methods of representing Boolean algebra and show their equivalence.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc107933/

### Elliptic Geometry

**Date:**January 1966

**Creator:**Robertson, Barbara McKinzie

**Description:**This thesis discusses elliptic geometry including the order and incidence properties, projective properties and congruence properties.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc163883/

### Equivalence Classes of Cauchy Sequences of Rational Numbers

**Date:**January 1965

**Creator:**Darnell, Linda Jane

**Description:**The purpose of this thesis is to define equivalence classes of Cauchy sequences of rational numbers and the operations of taking a sum and a product and then to show that this system is an uncountable, ordered, complete field. In so doing, a mathematical system is obtained which is isomorphic to the real number system.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130561/

### Equivalence Classes of Subquotients of Pseudodifferential Operator Modules on the Line

**Date:**August 2012

**Creator:**Larsen, Jeannette M.

**Description:**Certain subquotients of Vec(R)-modules of pseudodifferential operators from one tensor density module to another are categorized, giving necessary and sufficient conditions under which two such subquotients are equivalent as Vec(R)-representations. These subquotients split under the projective subalgebra, a copy of ????2, when the members of their composition series have distinct Casimir eigenvalues. Results were obtained using the explicit description of the action of Vec(R) with respect to this splitting. In the length five case, the equivalence classes of the subquotients are determined by two invariants. In an appropriate coordinate system, the level curves of one of these invariants are a pencil of conics, and those of the other are a pencil of cubics.

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### Equivalent Sets and Cardinal Numbers

**Date:**December 1975

**Creator:**Hsueh, Shawing

**Description:**The purpose of this thesis is to study the equivalence relation between sets A and B: A o B if and only if there exists a one to one function f from A onto B. In Chapter I, some of the fundamental properties of the equivalence relation are derived. Certain basic results on countable and uncountable sets are given. In Chapter II, a number of theorems on equivalent sets are proved and Dedekind's definitions of finite and infinite are compared with the ordinary concepts of finite and infinite. The Bernstein Theorem is studied and three different proofs of it are given. In Chapter III, the concept of cardinal number is introduced by means of two axioms of A. Tarski, and some fundamental theorems on cardinal arithmetic are proved.

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### Euclidean N-space

**Date:**August 1962

**Creator:**Horner, Donald R.

**Description:**This study of the Euclidean N-space looks at some definitions and their characteristics, some comparisons, boundedness and compactness, and transformations and mappings.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc108157/

### Euclidean Rings

**Date:**May 1974

**Creator:**Fecke, Ralph Michael

**Description:**The cardinality of the set of units, and of the set of equivalence classes of primes in non-trivial Euclidean domains is discussed with reference to the categories "finite" and "infinite." It is shown that no Euclidean domains exist for which both of these sets are finite. The other three combinations are possible and examples are given. For the more general Euclidean rings, the first combination is possible and examples are likewise given. Prime factorization is also discussed in both Euclidean rings and Euclidean domains. For Euclidean rings, an alternative definition of prime elements in terms of associates is compared and contrasted to the usual definitions.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc663654/

### Examples and Applications of Infinite Iterated Function Systems

**Date:**August 2000

**Creator:**Hanus, Pawel Grzegorz

**Description:**The aim of this work is the study of infinite conformal iterated function systems. More specifically, we investigate some properties of a limit set J associated to such system, its Hausdorff and packing measure and Hausdorff dimension. We provide necessary and sufficient conditions for such systems to be bi-Lipschitz equivalent. We use the concept of scaling functions to obtain some result about 1-dimensional systems. We discuss particular examples of infinite iterated function systems derived from complex continued fraction expansions with restricted entries. Each system is obtained from an infinite number of contractions. We show that under certain conditions the limit sets of such systems possess zero Hausdorff measure and positive finite packing measure. We include an algorithm for an approximation of the Hausdorff dimension of limit sets. One numerical result is presented. In this thesis we also explore the concept of positively recurrent function. We use iterated function systems to construct a natural, wide class of such functions that have strong ergodic properties.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc2642/

### Exhaustibility and Related Set Properties

**Date:**1950

**Creator:**Cargal, Buchanan

**Description:**The purpose of this paper is to develop certain fundamental properties of exhaustible sets and their complements and to examine various set properties which are generalizations, with respect to exhaustible neglect, or well-known set properties.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130236/

### Exhaustivity, continuity, and strong additivity in topological Riesz spaces.

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

**Date:**May 2004

**Creator:**Muller, Kimberly O.

**Description:**In this paper, exhaustivity, continuity, and strong additivity are studied in the setting of topological Riesz spaces. Of particular interest is the link between strong additivity and exhaustive elements of Dedekind s-complete Banach lattices. There is a strong connection between the Diestel-Faires Theorem and the Meyer-Nieberg Lemma in this setting. Also, embedding properties of Banach lattices are linked to the notion of strong additivity. The Meyer-Nieberg Lemma is extended to the setting of topological Riesz spaces and uniform absolute continuity and uniformly exhaustive elements are studied in this setting. Counterexamples are provided to show that the Vitali-Hahn-Saks Theorem and the Brooks-Jewett Theorem cannot be extended to submeasures or to the setting of Banach lattices.

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### Existence and Uniqueness Theorems for Nth Order Linear and Nonlinear Integral Equations

**Date:**May 1969

**Creator:**Hurlbert, Gayle Jene Shultz

**Description:**The purpose of this paper is to study nth order integral equations. The integrals studied in this paper are of the Riemann type.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131097/

### Existence of a Sign-Changing Solution to a Superlinear Dirichlet Problem

**Date:**August 1995

**Creator:**Neuberger, John M. (John Michael)

**Description:**We study the existence, multiplicity, and nodal structure of solutions to a superlinear elliptic boundary value problem. Under specific hypotheses on the superlinearity, we show that there exist at least three nontrivial solutions. A pair of solutions are of one sign (positive and negative respectively), and the third solution changes sign exactly once. Our technique is variational, i.e., we study the critical points of the associated action functional to find solutions. First, we define a codimension 1 submanifold of a Sobolev space . This submanifold contains all weak solutions to our problem, and in our case, weak solutions are also classical solutions. We find nontrivial solutions which are local minimizers of our action functional restricted to various subsets of this submanifold. Additionally, if nondegenerate, the one-sign solutions are of Morse index 1 and the sign-changing solution has Morse index 2. We also establish that the action level of the sign-changing solution is bounded below by the sum of the two lesser levels of the one-sign solutions. Our results extend and complement the findings of Z. Q. Wang ([W]). We include a small sample of earlier works in the general area of superlinear elliptic boundary value problems.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc278179/

### Existence of a Solution for a Wave Equation and an Elliptic Dirichlet Problem

**Date:**May 1988

**Creator:**Sumalee Unsurangsie

**Description:**In this paper we consider an existence of a solution for a nonlinear nonmonotone wave equation in [0,π]xR and an existence of a positive solution for a non-positone Dirichlet problem in a bounded subset of R^n.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc331780/