The theory of discrete groups acting on finite dimensional Euclidean open balls by hyperbolic isometries was borne around the end of 19th century within the works of Fuchs, Klein and Poincaré. We develop the theory of discrete groups acting by hyperbolic isometries on the open unit ball of an infinite dimensional separable Hilbert space. We present our investigations on the geometry of limit sets at the sphere at infinity with an attempt to highlight the differences between the finite and infinite dimensional theories. We discuss the existence of fixed points of isometries and the classification of isometries. Various notions of discreteness that were equivalent in finite dimensions, no longer turn out to be in our setting. In this regard, the robust notion of strong discreteness is introduced and we study limit sets for properly discontinuous actions. We go on to prove a generalization of the Bishop-Jones formula for strongly discrete groups, equating the Hausdorff dimension of the radial limit set with the Poincaré exponent of the group. We end with a short discussion on conformal measures and their relation with Hausdorff and packing measures on the limit set.

Pour une représentation automorphe cuspidale de GL(2,F) avec F un corps de nombres totalement réel, tel que est de type (k, r) et satisfait une condition de pente non critique, l’on construit une distribution p-adique sur le groupe de Galois de l’extension abélienne maximale de F non ramifiée en dehors de p et 1. On démontre que la distribution obtenue est admissible et interpole les valeurs critiques de la fonction L complexe de la représentation automorphe. Cette construction est basée sur l’étude de la cohomologie de la variété modulaire de Hilbert à coefficients surconvergents. / For each cohomological cuspidal automorphic representation for GL(2,F) where F is a totally real number field, such that is of type (k, r) tand satisfies the condition of non critical slope we construct a p-adic distribution on the Galois group of the maximal abelian extension of F unramified outside p and 1. We prove that the distribution is admissible and interpolates the critical values of L-function of the automorphic representation. This construction is based on the study of the overconvergent cohomology of Hilbert modular varieties.

This thesis makes novel contributions to a problem of practical and theoretical importance, namely how to determine explicitly computable upper bounds for the Hausdorff distance of the spectra of two compact operators on a Hilbert space in terms of the distance of the two operators in operator norm. It turns out that the answer depends crucially on the speed of decay of the sequence of singular values of the two operators. To this end, 'compactness classes', that is, collections of operators the singular values of which decay at a certain speed, are introduced and their functional analytic properties studied in some detail. The main result of the thesis is an explicit formula for the Hausdorff distance of the spectra of two operators belonging to the same compactness class. Along the way, upper bounds for the resolvents of operators belonging to a particular compactness class are established, as well as novel bounds for determinants of trace class operators.

So, Tse Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 55-56). / Abstracts in English and Chinese. / Chapter 1 --- Geometric Quantization --- p.8 / Chapter 1.1 --- Motivation --- p.8 / Chapter 1.2 --- Prequantization --- p.10 / Chapter 1.3 --- Kahler Polarization --- p.14 / Chapter 1.4 --- Holomorphic Quantization and Fock Space --- p.17 / Chapter 1.4.1 --- Example: Fock Space --- p.19 / Chapter 2 --- Projectively Flat Connection --- p.21 / Chapter 2.1 --- Variation of Complex Structure --- p.21 / Chapter 2.2 --- Projectively Flat Connection on H --- p.24 / Chapter 2.2.1 --- Example of n= 1: --- p.30 / Chapter 3 --- Construction of Projectively Flat Connection --- p.34 / Chapter 3.1 --- Mechanism for Construction of Projectively Flat Con- nection --- p.34 / Chapter 3.2 --- K = C Case --- p.39 / Chapter 3.2.1 --- Identification of C´ؤlinear Complex Structures --- p.40 / Chapter 3.2.2 --- Projecitvely flat bundle on U(n)×U(n) --- p.43 / Chapter 3.2.3 --- Example of n=1 --- p.44 / Chapter 3.3 --- K = H Case --- p.45 / Chapter 3.3.1 --- Identification of H-linear Complex Structures --- p.46 / Chapter 3.3.2 --- Projecitvely flat bundle on SO*(4n) --- p.49 / Chapter 3.3.3 --- Example of n = 1 --- p.51 / Bibliography --- p.55

Hilbert-Huang Transform (HHT) is a data analysis tool, first developed in 1998, which can be used to extract the periodic components embedded within oscillatory data. This thesis is dedicated to the understanding, application, and development of this tool. First, the background theory of HHT will be described and compared with other spectral analysis tools. Then, a number of applications will be presented, which demonstrate the capability for HHT to dissect and analyze the periodic components of different oscillatory data. Finally, a new algorithm is presented which expands HHT ability to analyze discontinuous data. The sum result is the creation of a number of useful tools developed from the application of HHT, as well as an improvement of the HHT tool itself.

The construction of the generalized continuous wavelet transform (GCWT) on Hilbert spaces is a special case of the coherent state transform construction, where the coherent state system arises as an orbit of an admissible vector under a strongly continuous unitary representation of a locally compact group. In this thesis we extend this construction to the setting of Hilbert C*-modules. In particular, we define a coherent state transform and a GCWT on Hilbert modules. This construction gives a reconstruction formula and a resolution of the identity formula analogous to those found in the Hilbert space setting. Moreover, the existing theory of standard normalized tight frames in finite countably generated Hilbert modules can be viewed as a discrete case of this construction We also show that the image space of the coherent state transform on Hilbert module is a reproducing kernel Hilbert module. We discuss the kernel and the intertwining property of the group coherent state transform.

With the development of consumer electronics, the circuitry structure become more complex, For this reason, it might cause numerical errors to be cumulated in the simulation using the numerical electromagnetic algorithm, and result in simulated divergence or error. The two reasons of numerical error are passivity and causality, which priginate from the defect in the numerical calculation. In this thesis, for this problem, investigate the numerical compensation method for passivity, The occurrence of passive will make the frequency point of power is negative, this will makes the system divergence, Improve this problem, passivity verification and enforcement by eigenvalue in the Y-parameter, in the S-parameter by the singular value, causality conditions must be match with the imaginary part and the real part relationship, such as the Hilbert transform or the Kramer-Kronig relation, can be used to make causal verification and enforcement. Through some numerical methods, used simulation software such as: HFSS, ADS simulation of the microwave circuit model extraction, modified singular value, eigenvalue, and reached to reduce the numerical error, let it satisfy the convergence and avoid incorrect results, and minimize the impact of the initial data, does not change the characteristics of the original module, but also to solve the passive and the issue of causality.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 103-107). Available also in a digital version from Dissertation Abstracts.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 78-79). Also available in electronic version. Access restricted to campus users.