In this thesis we shall examine the role of measurability in the theory of Lebesgue Integration. This shall be done in the context of the real line where we define the notion of an integral of a bouuded real-valued function over a set of bounded outer measure without a prior assumption of measurability concerning the function and the domain of integration

Made available in DSpace on 2016-04-27T16:57:42Z (GMT). No. of bitstreams: 1 tese_luzia_aparecida_palaro.pdf: 27255885 bytes, checksum: d2ee8521118c71c7bfe212a84a1dfc70 (MD5) Previous issue date: 2006-05-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The main aim of this study was to consider the aspects which characterises Henri Lebesgue s conception of Mathematics Education. Lebesgue (1875-1941), as well as being one of the most eminent mathematicians of the twentieth century and revolutionising Mathematical Analysis with the creation of a new theory of measure and hence a new definition of the integral, was also a extremely dedicated teacher. Concerned about teacher education, he contributed much to debates on didactical, historical and philosophical issues related to Mathematics. The methodology adopted for this study was based on research with a bibliographic character, with a historic-descriptive approach employed, beginning with a brief presentation of the life and works of Lebesgue. Following this, a historicphilosophical contextualisation of Mathematics of his epoch is presented, along with a description of the philosophy of Mathematics he defended. To highlight the originality of Lebesgue s mathematical practices, a study of the historical development of Calculus from the seventeenth century until his time is presented, with the theory of functions serving as the leading thread of this development. Using as a basis this historical development, a study is made of how some Calculus and Analysis textbooks define Integration and how they approach the Fundamental Theorem of Calculus. Finally, a study of the work About the Measure of Magnitude is presented, which identifies aspects of the process that Lebesgue proposed for the teaching of mathematics. The study concludes that Lebesgue, given his constructivist stance: was not keen in the axiomatic tendency that characterised the practice of Mathematics during his time; that he placed emphasis on activity considering Mathematics as a tool without its own objects: that he defended a philosophy of Mathematics as simple and utilitarian, which would be a mere report on the practices of mathematician: and that he believed that teaching like the practice of Mathematicians, should begin with an activity which could be used as the basis from which to abstract concepts and make generalization, leaving the axiomatic definitions until the end / O objetivo geral deste trabalho foi levantar os aspectos caracterizadores da concepção de Educação Matemática de Henri Lebesgue (1875-1941), que além de ter sido um dos mais eminentes matemáticos do século XX pois revolucionou a Análise Matemática com a criação de uma nova teoria da medida e, fundamentado nesta, uma nova definição de integral , foi também um professor extremamente dedicado e que se preocupava com a formação de professores e, muito contribuiu para os assuntos didáticos, históricos e filosóficos da Matemática. A metodologia do estudo baseou-se em uma pesquisa de caráter bibliográfico, sob a abordagem histórico-descritiva; iniciando-se com uma breve apresentação da vida e das obras de Lebesgue. Em seguida, foram apresentadas uma contextualização histórico-filosófica da Matemática de sua época e a filosofia da Matemática que propagava. Buscando realçar a originalidade de Lebesgue, pela sua forma de fazer Matemática, foi apresentado um estudo do desenvolvimento histórico do Cálculo, do século XVII até Lebesgue, sendo a teoria das funções o fio condutor desse desenvolvimento. Tendo como base este desenvolvimento histórico, é apresentado um estudo de como alguns livros didáticos de Cálculo e Análise definem a integração e como abordam o Teorema Fundamental do Cálculo, identificando assim, a perspectiva adotada. Por fim, é apresentado um estudo da obra Sobre a Medida das Grandezas de autoria de Lebesgue, buscando identificar aspectos do processo que Lebesgue considerava para o ensino da Matemática. O estudo concluiu que Lebesgue, construtivista que era, não gostava da tendência axiomática de fazer Matemática de sua época; dava ênfase a atividade e considerava a Matemática um instrumento que não tem objetos próprios; propagava uma filosofia da Matemática simples e utilitária, que seria apenas um relato das práticas desenvolvidas pelos matemáticos; considerava que, no ensino assim como na prática de fazer matemática, se deveria iniciar com uma atividade, a partir da qual poderiam ser abstraídos conceitos, fazer generalizações, deixando as definições axiomáticas por último

In this thesis we shall examine the role of measurerability in the theory of Lebesgue Integration. This shall be done in the context of the real line where we define the notion of an integral of a bounded real-valued function over a set of bounded outer measure without a prior assumption of measurability concerning the function and the domain of integration. / Mathematical Sciences / M. Sc. (Mathematics)

In this thesis we shall examine the role of measurerability in the theory of Lebesgue Integration. This shall be done in the context of the real line where we define the notion of an integral of a bounded real-valued function over a set of bounded outer measure without a prior assumption of measurability concerning the function and the domain of integration. / Mathematical Sciences / M. Sc. (Mathematics)

A busca por grandes estruturas lineares em conjuntos de funções com propriedades pa-tológicas é um tópico que fora desenvolvido nos últimos vinte anos. Esse trabalho detalhaalguns desses resultados sobre lineabilidade e espaçabilidade de forma clara e diluida parafacilitar a introdução desses conceitos para um pesquisador não familiarizado.Veremos que os seguintes conjuntos são lineáveis: funçõesCnão analíticas, funçõescom apenas uma quantidade finita de pontos de continuidade, funções cujas derivadas sãoilimitadas num intervalo fechado, funções sobrejetoras em todo lugar que se anulam quasesempre. Também mostraremos a espaçabilidade dos seguintes conjuntos: funções de variaçãolimitada com um conjunto denso de descontinuidades em salto e funções Lebesgue integráveisem [0,1] não essencialmente limitadas em nenhum intervalo. Finalmente, veremos algunsresultados sobre a lineabilidade no conjunto dos funcionais lineares que atingem a norma. / Finding large linear structures in sets of functions with pathological properties is a topicthat has been developed in the last twenty years. This work details some of these resultsabout lineability and spaceability in a clear and diluted way to make the introduction ofthese concepts easier for an unfamiliar researcher.We show that the following sets are lineable:Cnon-analytic functions, functions witha finite number of points of continuity, functions whose derivative is unbounded on a closedinterval and everywhere surjective functions that are almost everywhere zero. We also showthe spaceability of the following sets: functions of bounded variation which have a denseset of jump discontinuities and Lebesgue integrable functions in [0,1] which are nowhereessentially bounded. At last, we show some results about lineability in the set of linearfunctionals that attain their norm.

Doctor of Philosophy / Department of Mathematics / Virginia Naibo / Investigations of pseudodifferential operators are useful in a variety of applications. These include finding solutions or estimates of solutions to certain partial differential equations, studying boundedness properties of commutators and paraproducts, and obtaining fractional Leibniz rules. A pseudodifferential operator is given through integration involving the Fourier transform of the arguments and a function called a symbol. Pseudodifferential operators were first studied in the linear case and results were obtained to advance both the theory and applicability of these operators. More recently, significant progress has been made in the study of bilinear, and more generally multilinear, pseudodifferential operators. Of special interest are boundedness properties of bilinear pseudodifferential operators which have been examined in a variety of function spaces. Since determining factors in the boundedness of these operators are connected to properties of the corresponding symbols, significant effort has been directed at categorizing the symbols according to size and decay conditions as well as at establishing the associated symbolic calculus. One such category, the bilinear Hörmander classes, plays a vital role in results concerning the boundedness of bilinear pseudodifferential operators in the setting of Lebesgue spaces in particular. The new results in this work focus on the study of bilinear pseudodifferential operators with symbols in weighted Besov spaces of product type. Unlike the Hörmander classes, symbols in these Besov spaces are not required to possess in finitely many derivatives satisfying size or decay conditions. Even without this much smoothness, boundedness properties on Lebesgue spaces are obtained for bilinear operators with symbols in certain Besov spaces. Important tools in the proofs of these new results include the demonstration of appropriate estimates and the development of a symbolic calculus for some of the Besov spaces along with duality arguments. In addition to the new boundedness results and as a byproduct of studying operators with symbols in Besov spaces, it is possible to quantify the smoothness of the symbols, in terms of the conditions that define the Hörmander classes, that is sufficient for boundedness of the operators in the context of Lebesgue spaces.

Notre travail se consacre à l’étude de l’existence de solution T-anti-périodique de l’équation de Liénard dans le cas impulsif. Dans notre thèse, cette équation sera appliquée à l’équation du pendule simple, de Josephson dans la super-conductivité et enfin à l’équation de Van der Pol pour modéliser un circuit de triode à tube vide. On considérera [florin] et J des actions extérieures sur le système où [florin] est une force Lebesgue intégrable (respectivement Henstock-Kurzweil intégrable au second chapitre) et J (parfois noté I) une stimulation impulsive. En appliquant le théorème du point fixe de Banach, on obtient des théorèmes d’existence de solution au sens de fonctions généralisées soumise à un ensemble de conditions données par les bornes à priori. Ensuite, par le même théorème, la suite d’itérations G[indice supérieur n] ([théta][indice inférieur 0]) converge uniformément vers la solution [théta] à la vitesse de convergence bornée avec la première dérivée […] est de variation totale finie sur [0; 2T] et la dérivée seconde généralisée […] Lebesgue intégrable sur [0; 2T] dans le cas non impulsif. Finalement, sous les mêmes hypothèses avec [florin] Henstock-Kurzweil (HK) intégrable, nous obtiendrons des conditions qui garantissent l’existence d’une solution T-antipériodique [théta] absolument continue sur R de l’équation de Liénard, qui admet à la fois une dérivée première […] de variation bornée et la seconde dérivée généralisée […] qui est HK--intégrable dans le cas non impulsif. Comme au premier chapitre nous considérerons également le cas des instants d’impulsion [gamma][indice inférieur kappa] indépendants d’état avec [florin] HK--intégrable. À chaque fois nous donnons quelques exemples d’illustration pour appuyer nos résultats. [Certains symboles non conformes]

Orientador: Marta Cilene Gadotti / Banca: Paulo Leandro Dattori da Silva / Banca: Ricardo Parreira da Silva / Resumo: Este trabalho apresenta resultados importantes sobre a Teoria de Integração. Inicialmente é desenvolvida uma parte sobre Teoria da Medida, necessária para introduzir a integral de Lebesgue e suas propriedades. Também é apresentada a integral de Riemann-Stieltjes. Em seguida, são demonstrados resultados importantes sobre converg ência envolvendo as integrais de Lebesgue, resultados estes que não são válidos para integrais de Riemann. Para apresentar tais temas, usa-se mais fortemente as referências [1], [2], [3] e [4] / Abstract: This study presents important results on Integration of Theory. The rst of all part is developed on Measure Theory which is necessary to introduce the Lebesgue integral and its properties and we introduce. It also shows the Riemann-Stieltjes integral. Important results are proved on convergence involving the integrals of Lebesgue, which are not valid for the Riemann integral. Im order to present these themes we strongly use the references [1], [2], [3] and [4] / Mestre

In this dissertation we investigate Lagrange interpolation. Our first result will deal with a hierarchy of interpolation schemes. Specifically, we will show that given a triangular array of points in a regular compact set K, such that the corresponding Lebesgue constants are subexponential, one always has the uniform convergence of Ln(f) to f for all functions analytic on K. We will then show that uniform convergence of Ln(f) to f for all analytic functions f is equivalent to the fact that the probability measures γn = 1/n Σn j=1 δzn,j , which are associated with our triangular array, converge weak star to the equilibrium distribution for K. Motivated by our hierarchy, we will then come to our main result, namely that the Lebesgue constants associated with Leja sequences on fairly general compact sets are subexponential. More generally, considering Newton interpolation on a sequence of points, we will show that the weak star convergence of their corresponding probability measures to the equilibrium distribution, together with a certain distancing rule, implies that their corresponding Lebesgue constants are sub-exponential.

<p>This paper deals with Lebesgue points and studies properties of the set of Lebesgue points for various classes of functions. We consider continuous functions, L¹ functions and Sobolev functions. In the case of uniformly continuous functions and Hölder continuous functions we develop a characterization in terms of Lebesgue points. For Sobolev functions we study the dimension of the set of non-Lebesgue points.</p>