Browsing Department of Mathematics by Title
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Eigenvalue comparison theorems for certain boundary value problems and positive solutions for a fifth order singular boundary value problem.
(20160323)Comparison of smallest eigenvalues for certain two point boundary value problems for a fifth order linear differential equation are first obtained. The results are extended to (2n+1)order and (3n+2)order boundary value ... 
Existence and uniqueness of solutions of boundary value problems by matching solutions.
(, 20130924)In this dissertation, we investigate the existence and uniqueness of boundary value problems for the third and nth order differential equations by matching solutions. Essentially, we consider the interval [a, c] of a BVP ... 
Existence of positive solutions to right focal three point singular boundary value problems.
(, 20130916)In this dissertation, we prove the existence of positive solutions to two classes of three point right focal singular boundary value problems of at least fourth order. 
Existence of positive solutions to singular right focal boundary value problems.
(Orlando, FL : International Publications., 200505)In this dissetation, we seek positive solutions for the n^th order ordinary differential equation, y^(n)=f(x,y), satisfying the right focal boundary conditions, y^(i)(0)=y^(n2)(p)=y^(n1)(1)=0, i=0,...,n3, where p is a ... 
GlazmanKreinNaimark theory, leftdefinite theory, and the square of the Legendre polynomials differential operator.
(20160227)As an application of a general leftdefinite spectral theory, Everitt, Littlejohn and Wellman, in 2002, developed the leftdefinite theory associated with the classical Legendre selfadjoint secondorder differential ... 
Global SL(2,R) representations of the Schrödinger equation with timedependent potentials.
(, 20120808)We study the representation theory of the solution space of the onedimensional Schrödinger equation with timedependent potentials that possess sl₂symmetry. We give explicit local intertwining maps to multiplier ... 
Indecomposability in inverse limits.
(20101008)Topological inverse limits play an important in the theory of dynamical systems and in continuum theory. In this dissertation, we investigate classical inverse limits of Julia sets and setvalued inverse limits of arbitrary ... 
Krylov methods for solving a sequence of large systems of linear equations.
(20150722)Consider solving a sequence of linear systems A_{(i)}x^{(i)}=b^{(i)}, i=1, 2, ... where A₍ᵢ₎ ϵℂⁿᵡⁿ and b⁽ⁱ⁾ϵℂⁿ using some variations of Krylov subspace methods, like GMRES. For a single system Ax=b, it is wellknown that ... 
The leftdefinite spectral analysis of the legendre type differential equation.
(20100202)Littlejohn and Wellman developed a general abstract leftdefinite theory for a selfadjoint operator A that is bounded below in a Hilbert space (H,(‧,‧)). More specifically, they construct a continuum of Hilbert spaces ... 
Local automorphisms of finitary incidence algebras.
(20170707)Let $R$ be a commutative, indecomposable ring with identity and let $(P,\le)$ be a locally finite partially ordered set. Let $FI(P)$ denote the finitary incidence algebra of $(P,\le)$ over $R$. In this case, the finitary ... 
Moment representations of exceptional orthogonal polynomials.
(20180712)Exceptional orthogonal polynomials (XOPs) can be viewed as an extension of their classical orthogonal polynomial counterparts. They exclude polynomials of a certain order(s) from being eigenfunctions for their corresponding ... 
On a ring associated to F[x].
(, 20130924)For a ﬁeld F and the polynomial ring F [x] in a single indeterminate, we deﬁne Ḟ [x] = {α ∈ End_F(F [x]) : α(ƒ) ∈ ƒF [x] for all ƒ ∈ F [x]}. Then Ḟ [x] is naturally isomorphic to F [x] if and only if F is inﬁnite. If F ... 
On BirmanHardyRellichtype inequalities.
(20190724)In 1961, Birman proved a sequence of inequalities on the space of mtimes continuously di↵erentiable functions of compact support Cm 0 ((0, 1)) ⇢ L2((0, 1)), containing the classical (integral) Hardy inequality and the ... 
Orbit structures of homeomorphisms.
(, 20121129)In this dissertation we answer the following question: If X is a Cantor set and T: X → to X is a homeomorphism, what possible orbit structures can T have? The answer is given in terms of the orbit spectrum of T. If X is a ... 
Orbits, pseudo orbits, and the characteristic polynomial of qnary quantum graphs.
(20200717)Quantum graphs provide a simple model of quantum mechanics in systems with complex geometry and can be used to study quantum chaos. We evaluate the variance of the coefficients of a quantum binary graph’s associated ... 
Oscillating satellites about the straight line equilibrium points.
(1952)The problem as studied in this thesis is the behavior of a satellite at the three equilibrium points. When a satellite is displaced from rest at one of these points it will either oscillate or rapidly leave the system. The ... 
Polynomial preconditioning with the minimum residual polynomial.
(20191217)Krylov subspace methods are often used to solve large, sparse systems of linear equations Ax=b. Preconditioning can help accelerate the Krylov iteration and reduce costs for solving the problem. We study a polynomial ... 
Preconditioning mixed finite elements for tide models.
(20190724)We describe finite element methods for the linearized rotating shallow water equations which govern tides. Symplectic Euler and CrankNicolson timestepping strategies have good energy preservation properties, which is ... 
Quadratic Lyapunov theory for dynamic linear switched systems.
(, 20140128)In this work, a special class of timevarying linear systems in the arbitrary time scale setting is examined by considering the qualitative properties of their solutions. Building on the work of J. DaCunha and A. Ramos, ... 
Restarting the Lanczos algorithm for large eigenvalue problems and linear equations.
(20081002)We are interested in computing eigenvalues and eigenvectors of large matrices and in solving large systems of linear equations. Restarted versions of both the symmetric and nonsymmetric Lanczos algorithms are given. For ...