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Physical Sciences and Mathematics

East Tennessee State University

Theses/Dissertations

Graph Theory

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Decompositions Of The Complete Mixed Graph By Mixed Stars, Chance Culver Aug 2020

Decompositions Of The Complete Mixed Graph By Mixed Stars, Chance Culver

Electronic Theses and Dissertations

In the study of mixed graphs, a common question is: What are the necessary and suffcient conditions for the existence of a decomposition of the complete mixed graph into isomorphic copies of a given mixed graph? Since the complete mixed graph has twice as many arcs as edges, then an obvious necessary condition is that the isomorphic copies have twice as many arcs as edges. We will prove necessary and suffcient conditions for the existence of a decomposition of the complete mixed graphs into mixed stars with two edges and four arcs. We also consider some special cases of decompositions …


The 2-Domination Number Of A Caterpillar, Presley Chukwukere Aug 2018

The 2-Domination Number Of A Caterpillar, Presley Chukwukere

Electronic Theses and Dissertations

A set D of vertices in a graph G is a 2-dominating set of G if every vertex in V − D has at least two neighbors in D. The 2-domination number of a graph G, denoted by γ2(G), is the minimum cardinality of a 2- dominating set of G. In this thesis, we discuss the 2-domination number of a special family of trees, called caterpillars. A caterpillar is a graph denoted by Pk(x1, x2, ..., xk), where xi is the number of leaves attached to the ith vertex …


Differentiating Between A Protein And Its Decoy Using Nested Graph Models And Weighted Graph Theoretical Invariants, Hannah E. Green May 2017

Differentiating Between A Protein And Its Decoy Using Nested Graph Models And Weighted Graph Theoretical Invariants, Hannah E. Green

Electronic Theses and Dissertations

To determine the function of a protein, we must know its 3-dimensional structure, which can be difficult to ascertain. Currently, predictive models are used to determine the structure of a protein from its sequence, but these models do not always predict the correct structure. To this end we use a nested graph model along with weighted invariants to minimize the errors and improve the accuracy of a predictive model to determine if we have the correct structure for a protein.


General Bounds On The Downhill Domination Number In Graphs., William Jamieson May 2013

General Bounds On The Downhill Domination Number In Graphs., William Jamieson

Undergraduate Honors Theses

A path π = (v1, v2,...vk+1) in a graph G = (V,E) is a downhill path if for every i, 1 < i < k, deg(vi) > deg(vi+1), where deg(vi) denotes the degree of vertex viV. The downhill domination number equals the minimum cardinality of a set S ⊂ V having the property that every vertex vV lies on a downhill path originating from some vertex in S. We investigate downhill domination numbers of graphs and give upper bounds. …


Global Domination Stable Graphs, Elizabeth Marie Harris Aug 2012

Global Domination Stable Graphs, Elizabeth Marie Harris

Electronic Theses and Dissertations

A set of vertices S in a graph G is a global dominating set (GDS) of G if S is a dominating set for both G and its complement G. The minimum cardinality of a global dominating set of G is the global domination number of G. We explore the effects of graph modifications on the global domination number. In particular, we explore edge removal, edge addition, and vertex removal.


On The Attainability Of Upper Bounds For The Circular Chromatic Number Of K4-Minor-Free Graphs., Tracy Lance Holt May 2008

On The Attainability Of Upper Bounds For The Circular Chromatic Number Of K4-Minor-Free Graphs., Tracy Lance Holt

Electronic Theses and Dissertations

Let G be a graph. For kd ≥ 1, a k/d -coloring of G is a coloring c of vertices of G with colors 0, 1, 2, . . ., k - 1, such that d ≤ | c(x) - c(y) | ≤ k - d, whenever xy is an edge of G. We say that the circular chromatic number of G, denoted χc(G), is equal to the smallest k/d where a k/d -coloring exists. In [6], Pan and …