Browsing Theses by Subject "combinatorics"
Now showing items 1-20 of 26
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Algorithms for Analytic Combinatorics in Several Variables
(University of Waterloo, 2023-04-25)Given a multivariate rational generating function we are interested in computing asymptotic formulas for the sequences encoded by the coefficients. In this thesis we apply the theory of analytic combinatorics in several ... -
Bipartite Quantum Walks and the Hamiltonian
(University of Waterloo, 2023-09-26)We study a discrete quantum walk model called bipartite walks via a spectral approach. A bipartite walk is determined by a unitary matrix U, i.e., the transition matrix of the walk. For every transition matrix U, there is ... -
Combinatorial Constructions for Transitive Factorizations in the Symmetric Group
(University of Waterloo, 2004)We consider the problem of counting <i>transitive factorizations</i> of permutations; that is, we study tuples (σ<i>r</i>,. . . ,σ1) of permutations on {1,. . . ,<i>n</i>} such that (1) the product ... -
Combinatorial Generalizations of Sieve Methods and Characterizing Hamiltonicity via Induced Subgraphs
(University of Waterloo, 2022-08-17)A sieve method is in effect an application of the inclusion-exclusion counting principle, and the estimation methods to avoid computing the explicit formula. Sieve methods have been used in number theory for over a hundred ... -
Combinatorial Methods for Enumerating Maps in Surfaces of Arbitrary Genus
(University of Waterloo, 2016-06-10)The problem of map enumeration is one that has been studied intensely for the past half century. Early work on this subject included the works of Tutte for various types of rooted planar maps and the works of Brown for ... -
A Combinatorial Tale of Two Scattering Amplitudes: See Two Bijections
(University of Waterloo, 2022-01-07)In this thesis, we take a journey through two different but not dissimilar stories with an underlying theme of combinatorics emerging from scattering amplitudes in quantum field theories. The first part tells the tale ... -
Computational Methods for Combinatorial and Number Theoretic Problems
(University of Waterloo, 2017-04-27)Computational methods have become a valuable tool for studying mathematical problems and for constructing large combinatorial objects. In fact, it is often not possible to find large combinatorial objects using human ... -
Convex Algebraic Geometry Approaches to Graph Coloring and Stable Set Problems
(University of Waterloo, 2021-08-23)The objective of a combinatorial optimization problem is to find an element that maximizes a given function defined over a large and possibly high-dimensional finite set. It is often the case that the set is so large that ... -
Core Structures in Random Graphs and Hypergraphs
(University of Waterloo, 2013-08-30)The k-core of a graph is its maximal subgraph with minimum degree at least k. The study of k-cores in random graphs was initiated by Bollobás in 1984 in connection to k-connected subgraphs of random graphs. Subsequently, ... -
Developing a Generalized Model for Neutron Diffraction with Quantum Information Theory
(University of Waterloo, 2022-08-31)Due to their high mass and neutral electric charge, neutrons are often used at low energies to probe small-scale structures or measure fundamental constants of nature. To design neutron optical elements for use in these ... -
Differential Equations and Depth First Search for Enumeration of Maps in Surfaces
(University of Waterloo, 1999)A map is an embedding of the vertices and edges of a graph into a compact 2-manifold such that the remainder of the surface has components homeomorphic to open disks. With the goal of proving the Four Colour Theorem, ... -
Graph-Theoretic Techniques for Optimizing NISQ Algorithms
(University of Waterloo, 2024-02-15)Entering the NISQ era, the search for useful yet simple quantum algorithms is perhaps of more importance now than it may ever be in the future. In place of quantum walks, the quantum Fourier transform, and asymptotic results ... -
Hamilton Paths in Generalized Petersen Graphs
(University of Waterloo, 2002)This thesis puts forward the conjecture that for <i>n</i> > 3<i>k</i> with <i>k</i> > 2, the generalized Petersen graph, <i>GP</i>(<i>n,k</i>) is Hamilton-laceable if <i>n</i> is even and <i>k</i> is odd, and it is ... -
Hurwitz Trees and Tropical Geometry
(University of Waterloo, 2016-01-21)The lifting problem in algebraic geometry asks when a finite group G acting on a curve defined over characteristic p > 0 lifts to characteristic 0. One object used in the study of this problem is the Hurwitz tree, which ... -
Local Structure for Vertex-Minors
(University of Waterloo, 2021-10-12)This thesis is about a conjecture of Geelen on the structure of graphs with a forbidden vertex-minor; the conjecture is like the Graph Minors Structure Theorem of Robertson and Seymour but for vertex-minors instead of ... -
A mathematical foundation for the use of cliques in the exploration of data with navigation graphs
(University of Waterloo, 2023-01-19)Navigation graphs were introduced by Hurley and Oldford (2011) as a graph-theoretic framework for exploring data sets, particularly those with many variables. They allow the user to visualize one small subset of the variables ... -
Modularity and Structure in Matroids
(University of Waterloo, 2013-04-22)This thesis concerns sufficient conditions for a matroid to admit one of two types of structural characterization: a representation over a finite field or a description as a frame matroid. We call a restriction N of a ... -
On Finding Large Cliques when the Chromatic Number is close to the Maximum Degree
(University of Waterloo, 2021-12-23)We prove that every graph G with chromatic number χ(G) = ∆(G) − 1 and ∆(G) ≥ 66 contains a clique of size ∆(G) − 17. Our proof closely parallels a proof from Cranston and Rabern, who showed that graphs with χ = ∆ and ∆ ≥ ... -
On Geometric Drawings of Graphs
(University of Waterloo, 2018-04-18)This thesis is about geometric drawings of graphs and their topological generalizations. First, we study pseudolinear drawings of graphs in the plane. A pseudolinear drawing is one in which every edge can be extended ... -
Quadratically Dense Matroids
(University of Waterloo, 2020-07-08)This thesis is concerned with finding the maximum density of rank-$n$ matroids in a minor-closed class. The extremal function of a non-empty minor-closed class $\mathcal M$ of matroids which excludes a rank-2 uniform ...