O principal objetivo deste trabalho é apresentar um estudo sistemático da teoria dos espaços topológicos resolúveis e irresolúveis. Enfocaremos diversas propriedades inerentes aos mesmos, incluindo uma exposição meticulosa de técnicas utilizadas na construção de espaços topológicos irresolúveis e sem pontos isolados. Dado um cardinal \\kappa > 1, exibiremos exemplos de espaços topológicos que são \\kappa-resolúveis, mas que não são \\kappa^{+}-resolúveis. Mostraremos, ainda, que se um espaço topológico for n-resolúvel, para todo número natural n, o mesmo será \\omega-resolúvel. Provaremos, contudo, que se \\lambda é um cardinal tal que \\omega < cf(\\lambda) = \\lambda, existe um espaço topológico que é \\mu-resolúvel, para todo cardinal \\mu < \\lambda, mas que não é \\lambda-resolúvel. O cerne desta dissertação refere-se à construção, em ZFC, de um subespaço enumerável, denso e submaximal de 2^c. / The main purpose of this work is to study the theory of resolvable and irresolvable topological spaces. We shall introduce many properties of these spaces and we shall give special attention to some techniques used in the construction of irresolvable topological spaces without isolated points. Given a cardinal \\kappa > 1, we will present some examples of topological spaces which are \\kappa-resolvable, but not \\kappa^{+}-resolvable. Besides, we will show that if a topological space is n-resolvable, for every natural number n > 1, then it is \\omega-resolvable too. Nevertheless, we shall prove that if \\lambda is a cardinal with \\omega < cf(\\lambda) = \\lambda, there is a topological space which is \\mu-resolvable, for each cardinal \\mu < \\lambda, but that is not \\lambda-resolvable. The backbone of this dissertation is the construction, in ZFC, of a countable, dense and submaximal subspaces of 2^c.

O principal objetivo deste trabalho é apresentar um estudo sistemático da teoria dos espaços topológicos resolúveis e irresolúveis. Enfocaremos diversas propriedades inerentes aos mesmos, incluindo uma exposição meticulosa de técnicas utilizadas na construção de espaços topológicos irresolúveis e sem pontos isolados. Dado um cardinal \\kappa > 1, exibiremos exemplos de espaços topológicos que são \\kappa-resolúveis, mas que não são \\kappa^{+}-resolúveis. Mostraremos, ainda, que se um espaço topológico for n-resolúvel, para todo número natural n, o mesmo será \\omega-resolúvel. Provaremos, contudo, que se \\lambda é um cardinal tal que \\omega < cf(\\lambda) = \\lambda, existe um espaço topológico que é \\mu-resolúvel, para todo cardinal \\mu < \\lambda, mas que não é \\lambda-resolúvel. O cerne desta dissertação refere-se à construção, em ZFC, de um subespaço enumerável, denso e submaximal de 2^c. / The main purpose of this work is to study the theory of resolvable and irresolvable topological spaces. We shall introduce many properties of these spaces and we shall give special attention to some techniques used in the construction of irresolvable topological spaces without isolated points. Given a cardinal \\kappa > 1, we will present some examples of topological spaces which are \\kappa-resolvable, but not \\kappa^{+}-resolvable. Besides, we will show that if a topological space is n-resolvable, for every natural number n > 1, then it is \\omega-resolvable too. Nevertheless, we shall prove that if \\lambda is a cardinal with \\omega < cf(\\lambda) = \\lambda, there is a topological space which is \\mu-resolvable, for each cardinal \\mu < \\lambda, but that is not \\lambda-resolvable. The backbone of this dissertation is the construction, in ZFC, of a countable, dense and submaximal subspaces of 2^c.

This work presents an overview of several different methods for construct- ing ultrafilters. The first part contains constructions not needing additional assumptions beyond the usual axioms of Set Theory. K. Kunen's method using independent systems for constructing weak P-points is presented. This is followed by a presentation of its application in topology (the proof of the existence of sixteen topological types due to J. van Mill). Finally a new con- struction due to the author is presented together with a proof of his result, the existence of a seventeenth topological type: ω∗ contains a point which is discretely untouchable, is a limit point of a countable set and the countable sets having it as its limit point form a filter. The second part looks at constructions which use additional combina- torial axioms and/or forcing. J. Ketonen's construction of a P-point and A. R. D. Mathias's construction of a Q-point are presented in the first two sections. The next sections concentrate on strong P-points introduced by C. Laflamme. The first of these contains a proof of a new characterization theorem due jointly to the author, A. Blass and M. Hrušák: An ultrafilter is Canjar if and only if it is a strong P-point. A new proof of Canjar's the- orem on the existence of non-dominating filters (Canjar filters) which uses...