Physical Sciences and Mathematics Commons^™

Left-Separation Of Ω1, Lukas Stuelke, Adrienne Stanley Ph.D.

Summer Undergraduate Research Program (SURP) Symposium

A topological space is left-separated if it can be well-ordered so that every initial segment is closed. Here, we show that all countable ordinal numbers are left-separated. We then prove that a similar method could not work for ω₁ , using the pressing-down lemma¹ . We finish by showing that a left-separating well-ordering on ω₁ necessarily leads to a contradiction.

Rendezvous Numbers Of Compact And Connected Spaces, Kevin Demler, Bill Wood Ph.D.

Summer Undergraduate Research Program (SURP) Symposium

The concept of a rendezvous number was originally developed by O. Gross in 1964, and was expanded upon greatly by J. Cleary, S. Morris, and D. Yost in 1986. This number exists for every metric space, yet very little is known about it, and it’s exact value for most spaces is not known. Furthermore, it’s exact value is difficult to calculate, and in most cases we can only find bounds for the value. We focused on their arguments using convexity and applied it to shapes in different metrics and graphs. Using sets of points that stood out (vertices, midpoints) as …

Properties Of Left-Separated Spaces And Their Unions, Eric Scheidecker

Dissertations and Theses @ UNI

Left-separated spaces are topological spaces which can be well ordered such that every initial segment is closed. In this paper, we examine what topological properties imply left-separation, and under what circumstances left-separation is preserved by unions. We also introduce several known theorems regarding elementary submodels as they are one of the primary tools that we use. We prove that for a topological space X;

1. If X has a point-countable base, then X is left-separated if and only if X has closed intersection with any elementary submodel M such that X ∈ M.

2. If every elementary submodel …

The Programmatic Manipulation Of Planar Diagram Codes To Find An Upper Bound On The Bridge Index Of Prime Knots, Genevieve R. Johnson

Dissertations and Theses @ UNI

The “bridge index” of a knot is the least number of maximal overpasses taken over all diagrams of the knot. A naïve method to determine the bridge index of a knot is to perform Reidemeister moves on diagrams of the knot, and this method quickly becomes tedious to implement by hand. In this paper, we introduce a sequence of Reidemeister moves which we call a “drag the underpass” move and prove how planar diagram codes change as Reidemeister moves are performed. We then use these results to programatically perform Reidemeister moves using Python 2.7 to calculate an upper bound on …

A Survey Of Butterfly Diagrams For Knots And Links, Mark Ronnenberg

Dissertations and Theses @ UNI

A “butterfly diagram” is a representation of a knot as a kind of graph on the sphere. This generalization of Thurston’s construction of the Borromean rings was introduced by Hilden, Montesinos, Tejada, and Toro to study the bridge number of knots. In this paper, we study various properties of butterfly diagrams for knots and links. We prove basic some combinatorial results about butterflies and explore properties of butterflies for classes of links, especially torus links. The Wirtinger presentation for the knot group will be adapted to butterfly diagrams, and we translate the Reidemeister moves for knot diagrams into so-called “butterfly …

Some Convergence Properties Of Minkowski Functionals Given By Polytopes, Jesse Moeller

Dissertations and Theses @ UNI

In this work we investigate the behavior of the Minkowski Functionals admitted by a sequence of sets which converge to the unit ball ‘from the inside’. We begin in R 2 and use this example to build intuition as we extend to the more general R n case. We prove, in the penultimate chapter, that convergence ‘from the inside’ in this setting is equivalent to two other characterizations of the convergence: a geometric characterization which has to do with the sizes of the faces of each polytope in the sequence converging to zero, and the convergence of the Minkowski functionals …

Introduction To Fractal Geometry: Definition, Concept, And Applications, Mary Bond

Presidential Scholars Theses (1990 – 2006)

It has become evident that fractals are not to be tied down to one compact, Webster-style, paragraph definition. The foremost qualities of fractals include self-similarity and dimensionality. One cannot help but appreciate the aesthetic beauty of computer generated fractal art. Beyond these characteristics, when trying to grasp the idea of fractal geometry, it is helpful to learn about its many applications. Fractal geometry is opening new doors for study and understanding in diverse areas such as science, art, and music. All of these facets of fractal geometry unite to provide an intriguing, and alluring, wardrobe for mathematics to wear, so …

K Dimension Continued Fractions And K Dimension Golden Ratios, Tascha Gwyn Yoder

Presidential Scholars Theses (1990 – 2006)

The following is an investigation dealing with continued fractions based on research conducted by Professor John C. Longnecker at the University of Northern Iowa.