Sobriety of crisp and fuzzy topological spaces

The objective of this thesis is a survey of crisp and fuzzy sober topological spaces. We begin by examining sobriety of crisp topological spaces. We then extend this to the L- topological case and obtain analogous results and characterizations to those of the crisp case. We then brie y examine semi-sobriety of (L;M)-topological spaces

Sobriety of crisp and fuzzy topological spaces

The objective of this thesis is a survey of crisp and fuzzy sober topological spaces. We begin by examining sobriety of crisp topological spaces. We then extend this to the L- topological case and obtain analogous results and characterizations to those of the crisp case. We then brie y examine semi-sobriety of (L;M)-topological spaces

Topology from enrichment: the curious case of partial metrics

For any small quantaloid \Q, there is a new quantaloid \D(\Q) of diagonals in \Q. If \Q is divisible then so is \D(\Q) (and vice versa), and then it is particularly interesting to compare categories enriched in \Q with categories enriched in \D(\Q). Taking Lawvere's quantale of extended positive real numbers as base quantale, \Q-categories are generalised metric spaces, and \D(\Q)-categories are generalised partial metric spaces, i.e.\ metric spaces in which self-distance need not be zero and with a suitably modified triangular inequality. We show how every small quantaloid-enriched category has a canonical closure operator on its set of objects: this makes for a functor from quantaloid-enriched categories to closure spaces. Under mild necessary-and-sufficient conditions on the base quantaloid, this functor lands in the category of topological spaces; and an involutive quantaloid is Cauchy-bilateral (a property discovered earlier in the context of distributive laws) if and only if the closure on any enriched category is identical to the closure on its symmetrisation. As this now applies to metric spaces and partial metric spaces alike, we demonstrate how these general categorical constructions produce the "correct" definitions of convergence and Cauchyness of sequences in generalised partial metric spaces. Finally we describe the Cauchy-completion, the Hausdorff contruction and exponentiability of a partial metric space, again by application of general quantaloid-enriched category theory.Comment: Apart from some minor corrections, this second version contains a revised section on Cauchy sequences in a partial metric spac

L-fuzzy compactness and related concepts

The compactness defined by Warner and McLean is extended to arbitrary L-fuzzy sets where L is a fuzzy lattice, i.e., a completely distributive lattice with an order reversing involution. It is shown that with our compactness we can build up a satisfactory theory. The different definitions of compactness in L-fuzzy topological spaces are stated and other characterizations of some of these notions are obtained. We also study their goodness and establish the inter-relations between the compactnesses which are good extensions. Good definitions of L-fuzzy regularity and normality are proposed. Following the lines of our compactness we suggest two definitions of L-fuzzy local compactness that are good extensions of the respective ordinary versions. A comparison between them is presented and some of their properties studied. A one point compactification is also obtained. By introducing a new definition of a locally finite family of L-fuzzy sets and combining it with our definition of compactness, we propose an L-fuzzy paracompactness and study some of its properties. Good definitions of L-fuzzy countable and sequential compactness and the Lindelof property are introduced and studied. We also present, in L-fuzzy topological spaces, good extensions of S-closedness and RS-compactness. Some of their properties are examined. Good L-fuzzy versions of almost compactness, near compactness and a strong compactness are put forward and studied. A comparison between these compactness related concepts is also presented

Comparison of different notions of compactness in the fuzzy topological space

Various notions of compactness in a fuzzy topological space have been introduced by different authors. The aim of this thesis is to compare them. We find that in a T₂ space (in the sense that no fuzzy net converges to two fuzzy points with different supports) all these notions are equivalent for the whole space. Furthermore, for N-compactness and f-compactness (being the only notions that are defined for an arbitrary fuzzy subset) we have equivalence under a stronger condition, namely, a T₂ space in the sense that every prime prefilter has an adherence that is non-zero in at most one poin

Semi-lipschitz functions, best approximation, and fuzzy quasi-metric hyperspaces

En los últimos años se ha desarrollado una teoría matemática que permite generalizar algunas teorías matemáticas clásicas: hiperespacios, espacios de funciones, topología algebraica, etc. Este hecho viene motivado, en parte, por ciertos problemas de análisis funcional, concentración de medidas, sistemas dinámicos, teoría de las ciencias de la computación, matemática económica, etc. Esta tesis doctoral está dedicada al estudio de algunas de estas generalizaciones desde un punto de vista no simétrico. En la primera parte, estudiamos el conjunto de funciones semi-Lipschitz; mostramos que este conjunto admite una estructura de cono normado. Estudiaremos diversos tipos de completitud (bicompletitud, right k-completitud, D-completitud, etc), y también analizaremos cuando la casi-distancia correspondiente es balanceada. Además presentamos un modelo adecuado para el computo de la complejidad de ciertos algoritmos mediante el uso de normas relativas. Esto se consigue seleccionando un espacio de funciones semi-Lipschitz apropiado. Por otra parte, mostraremos que estos espacios proporcionan un contexto adecuado en el que caracterizar los puntos de mejor aproximación en espacios casi-métricos. El hecho de que varias hipertopologías hayan sido aplicadas con éxito en diversas áreas de Ciencias de la Computación ha contribuido a un considerable aumento del interés en el estudio de los hiperespacios desde un punto de vista no simétrico. Así, en la segunda parte de la tesis, estudiamos algunas condiciones de mejor aproximación en el contexto de hiperespacios casi-métricos. Por otro lado, caracterizamos la completitud de un espacio uniforme usando la completitud de Sieber-Pervin, la de Smyth y la D-completitud de su casi-uniformidad superior de Hausdorff-Bourbaki, definida en los subconjuntos compactos no vacíos. Finalmente, introducimos dos nociones de hiperespacio casi-métrico fuzzy.Sánchez Álvarez, JM. (2009). Semi-lipschitz functions, best approximation, and fuzzy quasi-metric hyperspaces [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/5769Palanci

Study of covering properties in fuzzy topology

This work is devoted to the study of covering properties both in L-fuzzy topological spaces and in smooth L-fuzzy topological spaces , that is the fuzzy spaces in Sostak's sense, where L is a fuzzy lattice . Based on the satisfactory theory of L-fuzzy compactness build up by Warner, McLean and Kudri, good definitions of feeble compactness and P-closedness are introduced and studied. A unification theory for good L-fuzzy covering axioms is provided. Following the lines of L-fuzzy compactness, we suggest two kinds of L-fuzzy relative compactness as in general topology, study some of their properties and prove that these notions are good extensions of the corresponding ordinary versions. We also present L-fuzzy versions of R-compactness , weak compactness and 0-rigidity and discuss some of their properties. By introducing 'a-Scott continuous functions', a 'goodness of extension' criterion for smooth fuzzy topological properties is established. We propose a good definition of compactness, which we call 'smooth compactness' in smooth L-fuzzy topological spaces. Smooth compactness turns out to be an extension of L-fuzzy compactness to smooth L-fuzzy topological spaces. We study some properties of smooth compactness and obtain different characterizations. As an extension of the fuzzy Hausdorffness defined by Warner and McLean, 'smooth Hausdorffness' is introduced in smooth L-fuzzy topological spaces. Good definitions of smooth countable compactness, smooth Lindelofness and smooth local compactness are introduced and some of their properties studied

Theoretical Interpretations and Applications of Radial Basis Function Networks

Medical applications usually used Radial Basis Function Networks just as Artificial Neural Networks. However, RBFNs are Knowledge-Based Networks that can be interpreted in several way: Artificial Neural Networks, Regularization Networks, Support Vector Machines, Wavelet Networks, Fuzzy Controllers, Kernel Estimators, Instanced-Based Learners. A survey of their interpretations and of their corresponding learning algorithms is provided as well as a brief survey on dynamic learning algorithms. RBFNs' interpretations can suggest applications that are particularly interesting in medical domains