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Full-Text Articles in Physical Sciences and Mathematics

The Hydrodynamic Flow Of Nematic Liquid Crystals In R3, Jay Lawrence Hineman Jan 2012

The Hydrodynamic Flow Of Nematic Liquid Crystals In R3, Jay Lawrence Hineman

Theses and Dissertations--Mathematics

This manuscript demonstrates the well-posedness (existence, uniqueness, and regularity of solutions) of the Cauchy problem for simplified equations of nematic liquid crystal hydrodynamic flow in three dimensions for initial data that is uniformly locally L3(R3) integrable (L3U(R3)). The equations examined are a simplified version of the equations derived by Ericksen and Leslie. Background on the continuum theory of nematic liquid crystals and their flow is provided as are explanations of the related mathematical literature for nematic liquid crystals and the Navier–Stokes equations.


Equivalence Theorems And The Local-Global Property, Aleams Barra Jan 2012

Equivalence Theorems And The Local-Global Property, Aleams Barra

Theses and Dissertations--Mathematics

In this thesis we revisit some classical results about the MacWilliams equivalence theorems for codes over fields and rings. These theorems deal with the question whether, for a given weight function, weight-preserving isomorphisms between codes can be described explicitly. We will show that a condition, which was already known to be sufficient for the MacWilliams equivalence theorem, is also necessary. Furthermore we will study a local-global property that naturally generalizes the MacWilliams equivalence theorems. Making use of F-partitions, we will prove that for various subgroups of the group of invertible matrices the local-global extension principle is valid.


Hilbert Polynomials And Strongly Stable Ideals, Dennis Moore Jan 2012

Hilbert Polynomials And Strongly Stable Ideals, Dennis Moore

Theses and Dissertations--Mathematics

Strongly stable ideals are important in algebraic geometry, commutative algebra, and combinatorics. Prompted, for example, by combinatorial approaches for studying Hilbert schemes and the existence of maximal total Betti numbers among saturated ideals with a given Hilbert polynomial, three algorithms are presented. Each of these algorithms produces all strongly stable ideals with some prescribed property: the saturated strongly stable ideals with a given Hilbert polynomial, the almost lexsegment ideals with a given Hilbert polynomial, and the saturated strongly stable ideals with a given Hilbert function. Bounds for the complexity of our algorithms are included. Also included are some applications for …


Lefschetz Properties And Enumerations, David Cook Ii Jan 2012

Lefschetz Properties And Enumerations, David Cook Ii

Theses and Dissertations--Mathematics

An artinian standard graded algebra has the weak Lefschetz property if the multiplication by a general linear form induces maps of maximal rank between consecutive degree components. It has the strong Lefschetz property if the multiplication by powers of a general linear form also induce maps of maximal rank between the appropriate degree components. These properties are mainly studied for the constraints they place, when present, on the Hilbert series of the algebra. While the majority of research on the Lefschetz properties has focused on characteristic zero, we primarily consider the presence of the properties in positive characteristic. We study …


Analytic And Topological Combinatorics Of Partition Posets And Permutations, Jiyoon Jung Jan 2012

Analytic And Topological Combinatorics Of Partition Posets And Permutations, Jiyoon Jung

Theses and Dissertations--Mathematics

In this dissertation we first study partition posets and their topology. For each composition c we show that the order complex of the poset of pointed set partitions is a wedge of spheres of the same dimension with the multiplicity given by the number of permutations with descent composition c. Furthermore, the action of the symmetric group on the top homology is isomorphic to the Specht module of a border strip associated to the composition. We also study the filter of pointed set partitions generated by knapsack integer partitions. In the second half of this dissertation we study descent …


Minimality And Duality Of Tail-Biting Trellises For Linear Codes, Elizabeth A. Weaver Jan 2012

Minimality And Duality Of Tail-Biting Trellises For Linear Codes, Elizabeth A. Weaver

Theses and Dissertations--Mathematics

Codes can be represented by edge-labeled directed graphs called trellises, which are used in decoding with the Viterbi algorithm. We will first examine the well-known product construction for trellises and present an algorithm for recovering the factors of a given trellis. To maximize efficiency, trellises that are minimal in a certain sense are desired. It was shown by Koetter and Vardy that one can produce all minimal tail-biting trellises for a code by looking at a special set of generators for a code. These generators along with a set of spans comprise what is called a characteristic pair, and we …


Rational Approximation On Compact Nowhere Dense Sets, Christopher Mattingly Jan 2012

Rational Approximation On Compact Nowhere Dense Sets, Christopher Mattingly

Theses and Dissertations--Mathematics

For a compact, nowhere dense set X in the complex plane, C, define Rp(X) as the closure of the rational functions with poles off X in Lp(X, dA). It is well known that for 1 ≤ p < 2, Rp(X) = Lp(X) . Although density may not be achieved for p > 2, there exists a set X so that Rp(X) = Lp(X) for p up to a given number greater than 2 but not after. Additionally, when p > 2 we shall establish that the support of the annihiliating and …