Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 32 for “"commutator"”.
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The annihilation graphs of commutator posets and lattices
… algebraic structure admitting a "good" theory of commutators is also considered.
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Flatness of the commutator map on special linear groups
… contributes to the study of the fibers of the commutator map on special linear groups in characteristic zero. Specifically, we show that the fibers over non-central elements all have the same dimension. Also we explain that the fibers over central elements can be of larger dimension and compute …
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The Smarandache vertices of the annihilation graphs of commutator posets and lattices with respect to an element and an ideal
… between the algebraic properties of the commutator posets and lattices and their associated annihilation graphs with respect to an element [resp. an ideal] using the notion of the Smarandache vertices. Actually, AGz(L) (the annihilation graph of the commutator poset [lattice] L with …
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On Loop Commutators, Quaternionic Automorphic Loops, and Related Topics
… Stanovský and Petr Vojtĕchovský, we study the commutator of congruences defined by Freese and McKenzie in order to create a more pleasing, equivalent definition of the commutator inside of loops. Moreover, we show that the commutator can be characterized by the generators of the inner mapping …
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Two applications of Berry's phase in fermionic field theory
… in a fermionic sea are studied: the anomalous commutator in gauge field theory and the intrinsic orbital angular momentum in superftuid 3He-A. Chapter 1 is a brief introduction. Chapter 2 reviews Berry's Phase and several toy models. Effective actions are calculated for two models in gradient …
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Almost commuting elements of real rank zero C∗-algebras
… operators in a Hilbert space H with their commutator [X; Y ] being small. Such operators are called almost commuting. How close is the pair X; Y to a pair of commuting operators X0; Y 0? In terms of one operator A = X + iY , suppose that the self-commutator [A;A] is small. How close is A to …
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Two applications of Berry's phase in fermionic field theory
… in a fermionic sea are studied: the anomalous commutator in gauge field theory and the intrinsic orbital angular momentum in superfluid $\sp3$He-A.
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Computations and lower bounds for scl and the relative Gromov seminorm
… is to give computations and estimates of stable commutator length, an invariant of groups that measures homological complexity and is connected to several notions of negative curvature in geometric group theory. A first aspect of this is to give exact computations, motivated by questions of …
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Ideals and Commutators of Operators
… operators with coefficient constraints. </p><p>Commutators of compact operators. The 1971 commutator problem asked by Pearcyand Topping is investigated: Is every compact operator a single commutator of compactoperators? And a 1976 test question arising from work of Pearcy, Topping, Anderson …
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Lifting Automorphisms to Stem Extensions of a Finite Group
… a stem extension of G if A is contained in the commutator subgroup E' of E. Schur showed that A must be isomorphic to a subgroup of the finite abelian group M = M(G) = H('2)(G,(//C)('(.))), where ((//C)('(.))) is the group of complex units. In case A (TURNEQ) M, we say that e is a stem cover of …
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Discrepancy Values and their Applications
… to achieve tight bounds on the norms of the commutator of two matrices and several other quantities. We finish the thesis by putting forward some conjectures regarding discrepancy values and discussing their implications.
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High accuracy computational methods for the semiclassical Schrödinger equation
… and numerical stability. The properties of commutator simplification and height reduction in these Lie algebras result in a highly effective form of $\textit{asymptotic splitting:} $exponential splittings where consecutive terms are scaled by increasing powers of the small semiclassical …
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Nilmanifolds: complex structures, geometry and deformations
… structures on nilpotent Lie algebras with small commutator subalgebra. MS Subject classification: 32G05; (32G08, 17B30, 53C30, 32C10)
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Fast Solvers for Models of Fluid Flow with Spectral Elements
… systems. We also extend the "least-squares commutator" preconditioner, originally developed for the finite element method, to a matrix-free spectral element framework. We show that these two advances, when used together, allow for efficient computation of steady-state solutions the the …
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Prethermalization and localization in quantum spin chains
… arises due to prethermalization, and the OTO commutator involving such prethermal conserved quantity saturates after a short time.
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Orders of Perfect Groups with Dihedral Involution Centralizers
Let G be a finite group that is equal to its commutator subgroup, and suppose that G contains an element of order 2 whose centralizer in G is dihedral of 2-power order. We study the cases where this centralizer is dihedral of order 8, 16, 32, 64, 128, or 256. It is true in each case that this …
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CHAOS, holography, and other science
… led to a simple diagnostic of many-body chaos: a commutator of such operators separated in time and space. Using this diagnostic, I study the growth of operators-a manifestation of the butterfly effect-in a variety of quantum systems. By considering the butterfly effect in holography, I find …
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Computer simulation of steady state and transient performance for permanent magnet DC motors
… to obtain the full characteristics of small commutator permanent magnet direct current motors. A comparison of the two methods is done in an attempt to obtain the most effective method of designing new motors. The comparison is done by calculating the performance of two segmental magnet de …
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Torque Controlled Drive for Permanent Magnet Direct Current Brushless Motors
… 60 ed to determine rotor position. An electronic commutator or phase switcher module interprets the position signals and produces a switching pattern. This effectively transforms the BLDC machine into a direct current (DC) brushed machine. A synchronous step down converter controls the BLDC …
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