[pt] Neste trabalho estudamos a teoria clássica das superfícies mínimas em R3, focando na representação de Enneper-Weierstrass e suas consequências. São exibidos vários exemplos, incluindo as superfícies de Jorge-Meeks e de Jorge-Xavier. Também mostramos princípios do máximo para superfícies mínimas e várias aplicações como, por exemplo, o teorema do semi-espaço. Em seguida, nos concentramos na teoria das superfícies mínimas completas de curvatura total finita e, com esta, podemos analisar o desenvolvimento assintótico de fins mínimos completos mergulhados de curvatura total finita. Por fim, a dissertação culmina com o teorema de Schoen, que afirma que as únicas superfícies mínimas completas, conexas, de curvatura total finita e apenas dois fins - ambos mergulhados - são um par de planos e o catenoide. / [en] In this work we study the classical theory of minimal surfaces in R3, with special focus on the Enneper-Weierstrass representation and its consequences. We exhibit many examples, including the Jorge-Meeks and Jorge-Xavier surfaces. We also show maximum principles for minimal surfaces and many applications as, for instance, the half-space theorem. Afterwards, we focus on the theory of complete minimal surfaces with finite total curvature, with which we can analyse the asymptotic development of complete minimal embedded ends with finite total curvature. This dissertation culminates with the Schoen s theorem, which states that the only complete, connected minimal surfaces with finite total curvature and exactly two ends - both embedded - are a pair of planes or a catenoid.

Made available in DSpace on 2015-05-15T11:45:59Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 323962 bytes, checksum: b1f72af0670744659eabe72c7c444dc3 (MD5) Previous issue date: 2008-08-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Weierstrass representation of minimal surfaces in R3 and its generalization to Rn shows is a very useful tool in the study of minimal surfaces in these spaces. In this work we want to describe a type Weierstrass representation for immersions simply connected in the group of Heisenberg H3. Using applications harmonics is possible obtain a formula for general representation, type Weierstrass for minimal immersions in manifolds Riemannian simply connected general, is that, useful of point view theoretical, however it is very difficult find solutions explicit. The dimention 3 and the structure of group Lie of the group of Heisenberg H3 allow a description Geometric simple and we can get some classic examples. / A representação deWeierstrass para superfícies mínimas em R3 e sua generalização a Rn mostra-se uma ferramenta muito útil no estudo de superfícies mínimas nestes espaços. Neste trabalho pretendemos descrever uma representação tipo Weierstrass para imersões simplesmente conexas no grupo de Heisenberg H3. Usando aplicações harmónicas é possível obter uma fórmula de representação geral, tipo Weierstrass, para imersões mínimas simplesmente conexas em variedades Riemannianas gerais, isto é útil do ponto de vista teórico, entretanto é muito difícil encontrar soluções explicitas. A dimensão 3 e a estrutura de grupo de Lie do grupo de Heisenberg H3 permitem uma descrição geométrica simples e podemos obter alguns exemplos clássicos.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / O trabalho traz inicialmente uma abordagem histÃrica, da GrÃcia (com os pitagÃricos), com o matemÃtico Eudoxo, fazendo referÃncia a talvez à maior obra matemÃtica, os livros de Euclides. Em seguida, trazemos definiÃÃes e construÃÃes sobre os nÃmeros reais com um corpo completo, os conceitos de Ãnfimo, supremo, sequÃncias infinitas com destaque as convergentes, sequÃncia de Cauchy e os trÃs teoremas fundamentais para o curso de cÃlculo, o teorema do anulamento, do valor intermediÃrio e de Weierstrass. Logo apÃs, definimos mÃtrica e espaÃo mÃtrico no plano, mostramos que o processo de comparar um segmento arbitrÃrio com outro fixado como unidade nos conduz aos diversos tipos de nÃmeros reais positivos: inteiros, racionais e irracionais, onde a noÃÃo de segmento comensurÃvel à explicada. O cÃlculo de Ãrea para figuras planas, onde sÃo apresentadas as fÃrmulas usuais para as Ãreas dos polÃgonos mais simples, apresentamos uma aplicaÃÃo, a fÃrmula de Pick, sem demonstraÃÃo do teorema, simples, divertida, prÃtica e eficiente para o cÃlculo de Ãrea, um conteÃdo da disciplina de matemÃtica presente em todo o ensino bÃsico do Brasil sempre presente em avaliaÃÃes externas como a OBMEP. / The work initially brings a historical approach, Greece (with the Pythagoreans), with the mathematician Eudoxus, referring to perhaps the greatest mathematical work, Euclidâs books. Then bring definitions and constructions of the real numbers as a complete body, the concepts of tiny, supreme, infinite sequences especially the convergent, Cauchy sequences and the three fundamental theorems for the calculus course, the annulment of the theorem, the intermediate value and Weierstrass. Soon after, we define metric and metric space in the plan, we show that the process of comparing an arbitrary segment with another set as unit leads to various types of positive real numbers: integers, rational and irrational, where the notion of measurable and immeasurable segment is explained. The area calculation for plane figures, where the usual formulas for the areas of simple polygons are presented, we present and application, Pickâs formula, without demonstration of the theorem, simple, fun, practical and efficient for area calculation, one this mathematical discipline of content throughout basic education in Brazil always present in external evaluation as OBMEP.

[pt] Há alguns anos temos visto um grande progresso na resolução de problemas antigos na teoria das superfícies mínimas. Dentre esse problemas estão as conjecturas de Calabi-Yau, que datam dos anos 60 do século passado. A primeira delas afirmava que não existiam superfícies mínimas completas contidas em uma bola de R3, e a segunda que todas as superfícies mínimas completas tinham uma projeção ilimitada em cada eixo. Neste trabalho pretendemos revisar dois exemplos que mostram a falsidade da segunda conjectura. O primeiro foi dado por L. P. Jorge e F. Xavier (1980), e o segundo por H. Rosenberg e E. Toubiana (1987). A primeira conjectura também é falsa. O primeiro contraexemplo foi dado por N. Nadirashvili (1996) e também constitui um contraexemplo da conjectura de Hadamard, que afirmava que não existiam superfícies completas limitadas com curvatura Gaussiana negativa. O desenvolvimento do artigo de Nadirashvili é o principal objetivo desta dissertação. A técnica usada nestes três trabalhos é o uso da Representação de Enneper-Weierstrass, combinada com aplicações adequadas do Teorema de Runge. / [en] During some years we have seen great progress in solving old problems in minimal surfaces theory. Among these problems are the Calabi-Yau s conjectures, dating from the 60s of last century. The first one stated that there were no complete minimal surfaces contained in a ball of R3, and the second one that all complete minimal surface should have an unbounded projection in each axes. In this work we pretend to review two examples that proof the falsity of the second conjecture. The first one was given by L. P. Jorge e F. Xavier (1980) and the second one by H. Rosenberg e E. Toubiana (1987). The first conjecture is also false. The first counterexample was given by N. Nadirashvili (1996) and it is also a counterexample to the conjecture of Hadamard, which stated that there were no complete bounded surfaces with negative Gaussian curvature. Development of Nadirashvilli s article is the main objective of this dissertation. The technique used in these three works is the use of the Enneper-Weierstrass Representation, combined with appropriate applications of Runge s theorem.

Orientador: Roberto Venegeroles Nascimento / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Matemática

Wir fixeren einen Körper k, der bezüglich eines nicht-archimedischen Absolutbetrags vollständig ist. In Kapitel 1 konstruieren wir eine Algebra U bestehend aus überkonvergenten Funktionen. Sie ist eine Unteralgebra der Tate-Algebra, wobei mittels einer sogenannten Filterfunktion, eine zusätzliche Wachstumsbedingung an die Koeffizienten der Potenzreihen in U gestellt wird. In diesem Kontext beweisen wir das folgende Resultat: U ist ein Noetherscher, Jacobsonscher, faktorieller Integritätsbereich, der bezüglich der Norm vollständig ist, und jedes Ideal in U ist abgeschlossen in der induzierten Topologie. In Kapitel 2 definieren wir die Kategorie der NMK-Algebren als die Kategorie der Quotienten der U. Indem wir in der größeren Kategorie der Frèchet-Räume arbeiten, beweisen wir die Noethernormalisierung und untersuchen die Morphismen zwishen NMK-Algebren. Schließlich zeigen wir, dass die Kategorie der NMK-Algebren abgeschlossen ist unter vervollständigten Tersorprodukten. In Kapitel 3 untersuchen wir geometrische Aspekte der Algebren U nämlich Eigenschaften der maximalen Ideale und die Regularität von U. Abschließend zeigen wir, dass für jedes U der assoziierte algebraische v exact in positiven Graden ist. / We fix a complete field k with respect to a non-Archimedean absolute value. In Chapter 1, we build the overconvergent function algebra U to be the subalgebra of the Tate algebra by putting a growth condition on the coefficients of the power series using a decreasing function which we call a filter function (satisfying certain conditions). With this setting we prove the following result: U is a Noetherian, Jacobson, unique factorization domain and it is complete with respect to the norm on it, moreover every ideal of U is closed with respect to the induced topology. In Chapter 2, we define a category of NMK-algebras as the category of all quotients of U. Working in the larger category of Frèchet spaces, we establish Noether normalization and investigate the morphisms between NMK-algebras. Finally, we show that the category of NMK-algebras is closed under completed tensor products. We investigate certain geometric aspects of the algebra U in Chapter 3, such as the properties of maximal ideals and regularity of U. Further, we show that for each U the associated algebraic de Rham complex is exact in positive degrees.

This report studies polynomial equations and how one solves them using only the coefficients of the polynomial. It examines why it is impossible to solve equations of degree greater than four using only radicals and how instead one can solve them using elliptic functions. Although the quintic equation is the main area of our investigation, we also present parts of the history of algebraic equations, Galois theory, and elliptic functions.

Made available in DSpace on 2014-06-11T19:22:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-25Bitstream added on 2014-06-13T20:28:17Z : No. of bitstreams: 1 arruda_rl_me_sjrp.pdf: 624072 bytes, checksum: 23ddd00e27d1ad781e2d1cec2cb65dee (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo principal deste trabalho é estudar o Teorema de Riemann-Roch, um dos resultados fundamentais na teoria de curvas algébricas, e apresentar algumas de suas aplicações. Este teorema é uma importante ferramenta para a classificação das curvas algébricas, pois relaciona propriedades algébricas e topológicas. Daremos uma descrição das curvas algébricas de gênero g, 1≤ g ≤ 5, e faremos um breve estudo dos pontos de inflexão de um sistema linear sobre uma curva algébrica / The main purpose of this work is to discuss The Riemann-Roch Theorem, wich is one of the most important results of the theory algebraic curves, and to present some applications. This theorem is an important tool of the classification of algebraic curves, sinces relates algebraic and topological properties. We will describle the algebraic curves of genus g, 1≤ g ≤ 5, and also study inflection points of a linear system on an algebraic curve

<p>This thesis surveys the issue of finding rational points on algebraic curves over finite fields. Since Goppa's construction of algebraic geometric codes, there has been great interest in finding curves with many rational points. Here we explain the main tools for finding rational points on a curve over a nite eld and provide the necessary background on ring and field theory. Four different articles are analyzed, the first of these articles gives a complete set of table showing the numbers of rational points for curves with genus up to 50. The other articles provide interesting constructions of covering curves: covers by the Hemitian curve, Kummer extensions and Artin-Schreier extensions. With these articles the great difficulty of finding explicit equations for curves with many rational points is overcome. With the method given by Arnaldo García in [6] we have been able to nd examples that can be used to define the lower bounds for the corresponding entries in the tables given in http: //wins.uva.nl/~geer, which to the time of writing this Thesis appear as "no information available". In fact, as the curves found are maximal, these entries no longer need a bound, they can be given by a unique entry, since the exact value of N_q(g) is now known.</p><p>At the end of the thesis an outline of the construction of Goppa codes is given and the NXL and XNL codes are presented.</p><p> </p>

This thesis surveys the issue of finding rational points on algebraic curves over finite fields. Since Goppa's construction of algebraic geometric codes, there has been great interest in finding curves with many rational points. Here we explain the main tools for finding rational points on a curve over a nite eld and provide the necessary background on ring and field theory. Four different articles are analyzed, the first of these articles gives a complete set of table showing the numbers of rational points for curves with genus up to 50. The other articles provide interesting constructions of covering curves: covers by the Hemitian curve, Kummer extensions and Artin-Schreier extensions. With these articles the great difficulty of finding explicit equations for curves with many rational points is overcome. With the method given by Arnaldo García in [6] we have been able to nd examples that can be used to define the lower bounds for the corresponding entries in the tables given in http: //wins.uva.nl/~geer, which to the time of writing this Thesis appear as "no information available". In fact, as the curves found are maximal, these entries no longer need a bound, they can be given by a unique entry, since the exact value of Nq(g) is now known. At the end of the thesis an outline of the construction of Goppa codes is given and the NXL and XNL codes are presented.