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**Partner:**UNT Libraries

**Degree Discipline:**Mathematics

**Collection:**UNT Theses and Dissertations

### 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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**Permallink:**digital.library.unt.edu/ark:/67531/metadc330641/

### 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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**Permallink:**digital.library.unt.edu/ark:/67531/metadc504338/

### 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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**Permallink:**digital.library.unt.edu/ark:/67531/metadc332102/

### 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/