Includes bibliographical references (p. 55-57).

Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 85-89).

Thesis (doctoral)--Rheinische Friedrich-Wilhelms-Universität Bonn, 1993. / Includes bibliographical references (p. 49-50).

Thesis (doctoral)--Rheinische Friedrich-Wilhelms-Universität Bonn, 1996. / Includes bibliographical references (p. 115-116).

Thesis (doctoral)--Rheinische Friedrich-Wilhelms-Universität Bonn, 1995. / Includes bibliographical references (p. 80-85).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

The class of pseudo-differential operators with symbols from Sm (superscript) po̧̧ (subscipt)(Ωx IRⁿ) has been extensively studied.The main assumption which characterises this class of symbols is that a(x,Ȩ) є Sm (superscript)po̧̧ (subscipt)(Ωx IRⁿ) should have a polynomial growth in the Ȩ variable only. The x-variable is controlled on compact subsets of Ω. A polynomial growth in both the x and Ȩ variables on a C°°(lR²ⁿ) function a(x,Ȩ) gives rise to a different class of symbols and a corresponding class of operators. In this work, such symbols and the action of the operators on the functional spaces S(lRⁿ) , S'(lRⁿ) and the Sobolev spaces Qs (superscript) (lRⁿ) (s є lRⁿ) are studied. A study of the calculus (i.e. transposes, adjoints and compositions) and the functional analysis of these operators is done with special attention to L-boundedness and compactness. The class of hypoelliptic pseudo-differential operators in IRⁿ is introduced as a subclass of those considered earlier.These operators possess the property that they allow a pseudo- inverse or parametrix. In conclusion. the spectral theory of these operators is considered. Since a general spectral theory would be beyond the scope of this work, only some special cases of the pseudo-differential operators in IRⁿ are considered. A few applications of this spectral theory are discussed

Nous nous intéressons aux formes modulaires surconvergentes définies sur certaines variétés de Shimura, et prouvons des théorèmes de classicité en grand poids. Dans un premier temps, nous étudions les variétés ayant bonne réduction, associées à des groupes non ramifiés en p. Nous nous intéressons aux variétés de Shimura PEL de type (A) et (C), qui sont associées respectivement à des groupes unitaires et symplectiques. Pour démontrer un théorème de classicité, nous utilisons la méthode du prolongement analytique, qui a été développée par Buzzard et Kassaei dans le cas de la courbe modulaire. Nous généralisons ensuite ce résultat de classicité à des variétés en ne supposant plus que le groupe associé est non ramifié en p. Dans le cas des formes modulaires de Hilbert, nous construisons des modèles entiers des compactifications de la variété, et démontrons un principe de Koecher. Pour des variétés de Shimura plus générales, nous travaillons avec le modèle rationnel de la variété, et utilisons un plongement vers une variété de Siegel pour définir les structures entières. / We deal with overconvergent modular forms défined on some Shimura varieties, andprove classicality results in the case of big weight. First we study the case of varieties with good reduction, associated to unramified groups in p. We deal with Shimura varieties of PEL type (A) and (C), which are associated respectively to unitary and symplectic groups. To prove a classicality theorem, we use the analytic continuation method, which has been developed by Buzzard and Kassaei in the case of the modular curve. We then generalize this classicality result for varieties without assuming that the associated group is unramified in p. In the case of Hilbert modular forms, we construct integral models of compactifications of the variety, and prove a Koecher principle. For more general Shimura varieties, we work with the rationnal model of the variety, and use an embedding to a Siegel variety to define the integral structures.

The LULU operators, Ln and Un, are smoothers, that is they smooth data received as a signal. They are nonlinear and this nonlinearity makes them more robust but also more complicated to study since the projection theorem does not hold. Their smoothing action is aimed at removing the impulsive noise present in any received signal. A signal can be of one or two dimensions, or of any higher dimension. In one dimension a signal is represented as a sequence and in two dimensions as an image. Higher dimensions include video feed and other more complex data streams. Carl Rohwer developed the LULU smoothers for sequences over the last three decades and the need for an extension to higher dimensions became more and more obvious as the applications of these smoothers were investigated. Perhaps the most important application is that of the Discrete Pulse Transform which is obtained via recursive application of the smoothers. In this dissertation the extension to dimensions higher than one is presented. All the essential properties developed for the one dimensional smoothers are replicated in this work. In addition, the Discrete Pulse Transform is used to illustrate some simple applications to image smoothing and feature detection. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Mathematics and Applied Mathematics / unrestricted