Browsing Combinatorics and Optimization by Title
Now showing items 305-324 of 434
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Packing and Covering Odd (u,v)-trails in a Graph
(University of Waterloo, 2016-09-27)In this thesis, we investigate the problem of packing and covering odd $(u,v)$-trails in a graph. A $(u,v)$-trail is a $(u,v)$-walk that is allowed to have repeated vertices but no repeated edges. We call a trail \emph{odd} ... -
Packing Directed Joins
(University of Waterloo, 2004)Edmonds and Giles conjectured that the maximum number of directed joins in a packing is equal to the minimum weight of a directed cut, for any weighted directed graph. This is a generalization of Woodall's Conjecture ... -
Parking Functions and Related Combinatorial Structures.
(University of Waterloo, 2001)The central topic of this thesis is parking functions. We give a survey of some of the current literature concerning parking functions and focus on their interaction with other combinatorial objects; namely noncrossing ... -
Partition Algebras and Kronecker Coefficients
(University of Waterloo, 2015-08-28)Classical Schur-Weyl duality relates the representation theory of the general linear group to the representation theory of the symmetric group via their commuting actions on tensor space. With the goal of studying Kronecker ... -
Partitioning Pauli Operators: in Theory and in Practice
(University of Waterloo, 2019-09-04)Measuring the expectation value of Pauli operators on prepared quantum states is a fundamental task in the variational quantum eigensolver. Simultaneously measuring sets of operators allows for fewer measurements and an ... -
Path Tableaux and the Combinatorics of the Immanant Function
(University of Waterloo, 2013-04-29)Immanants are a generalization of the well-studied determinant and permanent. Although the combinatorial interpretations for the determinant and permanent have been studied in excess, there remain few combinatorial ... -
Perfect Hash Families: Constructions and Applications
(University of Waterloo, 2003)Let <b>A</b> and <b>B</b> be finite sets with |<b>A</b>|=<i>n</i> and |<b>B</b>|=<i>m</i>. An (<i>n</i>,<i>m</i>,<i>w</i>)-<i>perfect hash</i> family</i> is a collection <i>F</i> of functions from <b>A</b> to <b>B</b> ... -
Piercing axis-parallel boxes
(The Electronic Journal of Combinatorics, 2018)Let F be a finite family of axis-parallel boxes in Rd such that F contains no k + 1 pairwise disjoint boxes. We prove that if F contains a subfamily M of k pairwise disjoint boxes with the property that for every F E F ... -
Planar graphs without 3-cycles and with 4-cycles far apart are 3-choosable
(University of Waterloo, 2016-09-16)A graph G is said to be L-colourable if for a given list assignment L = {L(v)|v ∈ V (G)} there is a proper colouring c of G such that c(v) ∈ L(v) for all v in V (G). If G is L-colourable for all L with |L(v)| ≥ k for all ... -
Plethysms of Chromatic and Tutte Symmetric Functions
(The Electronic Journal of Combinatorics, 2022)Plethysm is a fundamental operation in symmetric function theory, derived directly from its connection with representation theory. However, it does not admit a simple combinatorial interpretation, and finding coefficients ... -
Polyhedral Diameters and Applications to Optimization
(University of Waterloo, 2022-09-01)The Simplex method is the most popular algorithm for solving linear programs (LPs). Geometrically, it moves from an initial vertex solution to an improving neighboring one, selected according to a pivot rule. Despite decades ... -
Polynomial bounds for chromatic number II: Excluding a star-forest
(Wiley, 2022-10)The Gyárfás–Sumner conjecture says that for every forest H, there is a function fH such that if G is H-free then x(G) ≤ fH(w(G)) (where x,w are the chromatic number and the clique number of G). Louis Esperet conjectured ... -
Polynomial bounds for chromatic number. III. Excluding a double star
(Wiley, 2022-10)A “double star” is a tree with two internal vertices. It is known that the Gyárfás-Sumner conjecture holds for double stars, that is, for every double star H, there is a function fH such that if G does not contain H as ... -
Portfolio Selection Under Nonsmooth Convex Transaction Costs
(University of Waterloo, 2006)We consider a portfolio selection problem in the presence of transaction costs. Transaction costs on each asset are assumed to be a convex function of the amount sold or bought. This function can be nondifferentiable ... -
Post-Quantum Account Recovery for Passwordless Authentication
(University of Waterloo, 2023-04-24)WebAuthn is a passwordless authentication protocol which allows users to authenticate to online services using public-key cryptography. Users prove their identity based on possession of a private key, which is stored on a ... -
A post-quantum digital signature scheme based on supersingular isogenies
(University of Waterloo, 2017-09-20)We present the first general-purpose digital signature scheme based on supersingular elliptic curve isogenies secure against quantum adversaries in the quantum random oracle model with small key sizes. This scheme is ... -
Post-Quantum Security of Authenticated Key Establishment Protocols
(University of Waterloo, 2016-04-20)We present a security model for authenticated key establishment that allows for quantum interactions between the adversary and quantum oracles that emulate classical parties, resulting in a truly post-quantum security ... -
Postman Problems on Mixed Graphs
(University of Waterloo, 2003)The <i>mixed postman problem</i> consists of finding a minimum cost tour of a mixed graph <i>M</i> = (<i>V</i>,<i>E</i>,<i>A</i>) traversing all its edges and arcs at least once. We prove that two well-known linear ... -
Practical Lattice Cryptosystems: NTRUEncrypt and NTRUMLS
(University of Waterloo, 2015-12-22)Public key cryptography, as deployed on the internet today, stands on shaky ground. For over twenty years now it has been known that the systems in widespread use are insecure against adversaries equipped with quantum ... -
Preprocessing and Reduction for Semidefinite Programming via Facial Reduction: Theory and Practice
(University of Waterloo, 2013-11-26)Semidefinite programming is a powerful modeling tool for a wide range of optimization and feasibility problems. Its prevalent use in practice relies on the fact that a (nearly) optimal solution of a semidefinite program ...