We investigate properties of Koszmider spaces. We show that if K and L are compact Hausdor spaces with no isolated points, K is Koszmider and C(K) is isomorphic to C(L), then K and L are homeomorphic and, in particular, L is also Koszmider. We also analyse topological properties of Koszmider spaces and show that a connected Koszmider space is strongly rigid. In addition to Koszmider spaces, we introduce the notion of weakly Koszmider spaces. Having established an alternative characterisation thereof, we show that, while it is evident that every Koszmider space is weakly Koszmider, the reverse implication does not hold. We also prove that if C(K) and C(L) are isomorphic and K is weakly Koszmider, then so is L. However, if K is Koszmider, there always exists a non-Koszmider space L such that C(K) and C(L) are isomorphic. In the second part of the thesis we present two separable Koszmider spaces the construction of which does not use any set-theoretical assumptions except for the usual (ZFC) axioms. The first space is zero-dimensional, being the Stone space of a Boolean algebra. The second construction results in a separable connected Koszmider space.

In leading up to the proof, methods for constructing fields and finitely additive set functions are introduced with an application involving the Tagaki function given as an example. Also, non-absolutely continuous set functions are constructed using Banach limits and maximal filters.

Hardy-type operators involving suprema have turned out to be a useful tool in the theory of interpolation, for deriving Sobolev-type inequalities, for estimates of the non-increasing rearrangements of fractional maximal functions or for the description of norms appearing in optimal Sobolev embeddings. This thesis deals with the compactness of these operators on weighted Banach function spaces. We de ne a category of pairs of weighted Banach function spaces and formulate and prove a criterion for the compactness of a Hardy-type operator involving supremum which acts between a couple of spaces belonging to this category. Further, we show that the category contains speci c pairs of weighted Lebesgue spaces determined by a relation between the exponents. Besides, we bring an extension of the criterion to all weighted Lebesgue spaces, in proof of which we use characterization of the compactness of operators having the range in the cone of non-negative non-increasing functions, introduced as a separate result.

Neste trabalho estabelecemos algumas conseqüências da teoria do ponto fixo para aplicações tipo K-set contrativas e alguns simples resultados para multiaplicações no contexto de espaços de Banach. Os resultados apresentados, neste trabalho, para certas aplicações k-set contrativas e para aplicações pseudo-contrativas sob algumas condições adicionais, estão baseados nos estudos desenvolvidos por Petryshyn, Caristi Browder, C.Morales, Kirk & Shoneberg, e outros autores, enquanto os resultados obtidos para multiaplicações semicontínuas superiormente, sob condições tipo "inward"e para multiaplicações tipo o/ - condensativa, com respeito e alguma medida de não comparidade para sob algumas condições adicionais estão baseadas no trabalho de Browder, Caristi, Petryshyn & Fritzpatrick e Downing & Kirk.

No presente trabalho apresentamos dois teoremas obtidos por Gorak em 2011, que são generalizações para o Teorema de Banach-Stone, envolvendo uma classe de funções não-necessariamente lineares, denominadas quasi-isometrias. / In this work we present two theorems proved by Gorak in 2011. These results are generalizations of the Banach-Stone Theorem envolving a class of not-necessarily linear functions, called quasi-isometries.

by Zang Rui. / "Nov 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 78-82) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

No presente trabalho apresentamos dois teoremas obtidos por Gorak em 2011, que são generalizações para o Teorema de Banach-Stone, envolvendo uma classe de funções não-necessariamente lineares, denominadas quasi-isometrias. / In this work we present two theorems proved by Gorak in 2011. These results are generalizations of the Banach-Stone Theorem envolving a class of not-necessarily linear functions, called quasi-isometries.

We give an overview of Hahn-Banch Theorems. We present the statements of these theorems along with some definitions that are required to understand these statements and work out some applications.

This thesis is concerned with a class of general-purpose algorithms for constrained minimization problems, variational inequalities, and quasi-variational inequalities in Banach spaces. A substantial amount of background material from Banach space theory, convex analysis, variational analysis, and optimization theory is presented, including some results which are refinements of those existing in the literature. This basis is used to formulate an augmented Lagrangian algorithm with multiplier safeguarding for the solution of constrained optimization problems in Banach spaces. The method is analyzed in terms of local and global convergence, and many popular problem classes such as nonlinear programming, semidefinite programming, and function space optimization are shown to be included as special cases of the general setting. The algorithmic framework is then extended to variational and quasi-variational inequalities, which include, by extension, Nash and generalized Nash equilibrium problems. For these problem classes, the convergence is analyzed in detail. The thesis then presents a rich collection of application examples for all problem classes, including implementation details and numerical results. / Die vorliegende Arbeit handelt von einer Klasse allgemein anwendbarer Verfahren zur Lösung restringierter Optimierungsprobleme, Variations- und Quasi-Variationsungleichungen in Banach-Räumen. Zur Vorbereitung wird eine erhebliche Menge an Grundmaterial präsentiert. Dies beinhaltet die Theorie von Banach-Räumen, konvexe und variationelle Analysis sowie Optimierungstheorie. Manche der angegebenen Resultate sind hierbei Verfeinerungen der entsprechenden Ergebnisse aus der Literatur. Im Anschluss wird ein Augmented-Lagrange-Verfahren für restingierte Optimierungsprobleme in Banach-Räumen präsentiert. Der Algorithmus wird hinsichtlich lokaler und globaler Konvergenz untersucht, und viele typische Problemklassen wie nichtlineare Programme, semidefinite Programme oder Optimierungsprobleme in Funktionenräumen werden als Spezialfälle aufgezeigt. Der Algorithmus wird dann auf Variations- und Quasi-Variationsungleichungen verallgemeinert, wodurch implizit auch (verallgemeinerte) Nash-Gleichgewichtsprobleme abgehandelt werden. Für diese Problemklassen werden eigene Konvergenzanalysen betrieben. Die Dissertation beinhaltet zudem eine umfangreiche Sammlung von Anwendungsbeispielen und zugehörigen numerischen Ergebnissen.

The definition of semi-hyperbolic dynamical systems generated by Lipschitz continuous and not necessarily invertible mappings in Banach spaces is presented in this thesis. Like hyperbolic mappings, they involve a splitting into stable and unstable spaces, but a slight leakage from the strict invariance of the spaces is possible and the unstable subspaces are assumed to be finite dimensional. Bi-shadowing is a combination of the concepts of shadowing and inverse shadowing and is usually used to compare pseudo-trajectories calculated by a computer with the true trajectories. In this thesis, the concept of bi-shadowing in a Banach space is defined and proved for semi-hyperbolic dynamical systems generated by Lipschitz mappings. As an application to the concept of bishadowing, linear delay differential equations are shown to be bi-shadowing with respect to pseudo-trajectories generated by nonlinear small perturbations of the linear delay equation. This shows robustness of solutions of the linear delay equation with respect to small nonlinear perturbations. Complicated dynamical behaviour is often a consequence of the expansivity of a dynamical system. Semi-hyperbolic dynamical systems generated by Lipschitz mappings on a Banach space are shown to be exponentially expansive, and explicit rates of expansion are determined. The result is applied to a nonsmooth noninvertible system generated by delay differential equation. It is shown that semi-hyperbolic mappings are locally φ-contracting, where -0 is the Hausdorff measure of noncompactness, and that a linear operator is semi-hyperbolic if and only if it is φ-contracting and has no spectral values on the unit circle. The definition of φ-bi-shadowing is given and it is shown that semi-hyperbolic mappings in Banach spaces are φ-bi-shadowing with respect to locally condensing continuous comparison mappings. The result is applied to linear delay differential equations of neutral type with nonsmooth perturbations. Finally, it is shown that a small delay perturbation of an ordinary differential equation with a homoclinic trajectory is ‘chaotic’.