Nous étudions dans cette thèse la valeur spéciale des fonctions L des courbes elliptiques, et plus généralement des formes modulaires de poids 2, au premier point entier non critique, à<br />savoir s=2. Nous démontrons une version explicite d'un théorème de Beilinson relatif à cette valeur spéciale : pour toute forme parabolique primitive f de poids 2, niveau N ≥ 1 et caractère \psi, et pour tout caractère de Dirichlet \chi modulo N (pair, primitif et distinct du conjugué de \psi), nous exprimons L(f,2) L(f,\chi,1) comme régulateur d'un symbole de Milnor explicite associé à des unités modulaires de X_1(N). En niveau \Gamma_1(p), p premier, nous en déduisons que les symboles de Milnor associés aux unités modulaires de X_1(p) engendrent l'espace d'arrivée du régulateur de Beilinson. Utilisant l'appendice par Merel, nous donnons une formule explicite et universelle pour L(E,2), E courbe elliptique de conducteur p premier, en termes des valeurs tordues L(E,\chi,1), \chi caractère de conducteur p. Nous suggérons également une reformulation de la conjecture de Zagier pour L(E,2) au niveau de la jacobienne J_1(N) de X_1(N), où N est le conducteur de E. En ce sens, nous proposons un analogue du dilogarithme elliptique pour la jacobienne J d'une courbe algébrique : c'est une fonction R_J des points complexes de J vers le dual de l'espace des 1-formes différentielles holomorphes sur J. Nous montrons que L(f,2) L(f,\chi,1) est combinaison linéaire explicite de valeurs de R_{J_1(N)}, appliquée à f, en des points \Q-rationnels du sous-groupe cuspidal de J_1(N).

Nous étudions le comportement analytique de la fonction zêta associée à une certaine hauteur anticanonique sur une variété torique projective et lisse, le corps de définition étant un corps global de caractéristique positive. Ce comportement est étroitement lié à l'évolution asymptotique du nombre de points de hauteur bornée sur la variété. Manin et ses collaborateurs ont proposé des formules conjecturales pour le nombre de points de hauteur bornée sur une variété de Fano ou presque de Fano. Dans le cas des variétés toriques définies sur un corps de nombres ces formules ont été démontrées par Batyrev et Tschinkel, puis redémontrées par Salberger sous des hypothèses plus restrictives mais par une méthode entièrement différente. Nous nous intéressons donc dans cette thèse à la version fonctionnelle de ces résultats. Nous commençons par traiter le cas d'une variété torique déployée, en nous inspirant de la méthode de Salberger, basée sur une paramétrisation des points rationnels donnée par les torseurs universels ainsi que sur une inversion de Möbius. Nous expliquons ensuite comment les techniques utilisées dans cette situation peuvent s'appliquer aussi à un contexte motivique, mais notre calcul repose en partie sur une hypothèse non demontrée. Enfin pour examiner le cas de la compactification d'un tore non déployé nous adaptons au cas fonctionnel l'approche de Batyrev et Tshinkel. Leur idée est d'utiliser la formule de Poisson pour obtenir une représentation intégrale de la fonction zêta des hauteurs, intégrale que l'on évalue à l'aide du théorème des résidus. Nous obtenons une formule conforme aux prédictions de Manin et al., modulo le calcul d'un invariant du tore, invariant spécifique à la caractéristique non nulle. Nous n'avons pu mener à bien le calcul de cet invariant que pour des familles particulières de tores algébriques, et dans ce cas la formule obtenue est celle attendue. La question de savoir si la situation est la même pour un tore algébrique quelconque reste ouverte.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Esta dissertaÃÃo està dividida em dois capÃtulos. O primeiro capÃtulo apresenta os AnÃis de Grupos, os Grupos de Frobenius e suas respectivas propriedades. No inÃcio do segundo capÃtulo sÃo apresentadas as Conjecturas de Zassenhaus. A versÃo mais fraca dessas conjecturas à demonstrada para Grupos de Amitsur. No final do segundo capÃtulo, a validade dessa mesma versÃo à provada para Grupos de Frobenius.Tais Grupos de Frobenius sÃo aqueles cujo complemento verifica-se a validade dessa conjectura. Na parte final sÃo apresentados os subgrupos de Hall e o Teorema de Schur-Zassenhaus. / This dissertation is divided into two chapters. The first chapter introduces the Group Rings, the Frobenius Groups and their properties. In the beginning of the second chapter are presented Conjectures of Zassenhaus . The weaker version of these conjectures is demonstrated for Amitsur Groups. At the end of the second chapter, the validity of that version is proven to Frobenius Groups. Such Frobenius Groups are those whose complement, checks the validity of this conjecture. In the final part we present the Hall subgroups and Schur-Zassenhaus Theorem.

The influence of Chow groups on singular cohomology is motivated by classical results by Mumford and Roitman and has been investigated extensively. On the other hand, the converse influence is rather conjectural and it takes place in the framework of the ``philosophy of mixed motives'', which is mainly due to Grothendieck, Bloch and Beilinson. In the spirit of exploring this influence, Voisin formulated in 1996 a conjecture on 0--cycles on the self--product of surfaces of geometric genus one. There are few examples in which Voisin's conjecture has been verified, but it is still open for a general $K3$ surface. Our aim is to present a new example in which Voisin's conjecture is true, a family of Todorov surfaces. We give an explicit description of the family as quotient of complete intersection of four quadrics in $mathbb{P}^{6}$. We verify Voisin's conjecture for the family of Todorov surfaces of type $(2,12)$. Our main tool is Voisin's ``spreading of cycles'', we use it to establish a relation between 0--cycles on the Todorov surface and on the associated K3 surface. We give a motivic version of this result and some interesting motivic applications.

Made available in DSpace on 2016-04-27T16:58:28Z (GMT). No. of bitstreams: 1 Marcelo Eduardo Pereira.pdf: 4788851 bytes, checksum: f240246d61aa2e0ffdb09fe10593ffca (MD5) Previous issue date: 2007-10-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of this research is to analyze learning situations concerning argumentations and mathematical proofs combined with a computational tool and had been developed into the AprovaME project - Argumentação e Prova na Matemática Escolar (Argumentation and Proof in School Mathematics), particularly during the second phase. We are founded by researches that explore the assuming functions of proof as well as evaluate them in the school context, underneath various aspects and generality levels. Guided by the main results of this studies and the survey of proof conceptions made by the teenager students that had been accomplished during the first phase of the project, we prepared a sequence of activities intending to engage them throughout the stages of proving and to argue about the conditions of transiting between pragmatic and conceptual proofs. We search, into this context, to explore different functions proof, beyond the verification one, and to analyze the role of the Microsoft Excel tool in the students empirical work. The activities were applied in extra classes sessions for three pairs of volunteer students between 15-16 years old from a private school in Santos-SP. As result, it was verified that students interaction with the computer had dynamized the process of surveying conjectures and validating them. Also through the computer experience they were able to notice the manipulated objects properties which developed the production of justifications beyond empirical evidences. Therefore, within this proposal, the students had experienced the moments of proving and presented, by deductive reasoning, argumentations that show clearly the generality involved in the suggested tasks / A proposta deste trabalho é analisar situações de aprendizagem envolvendo argumentações e provas matemáticas, integrando uma ferramenta computacional, tendo sido desenvolvido no âmbito do projeto AProvaME Argumentação e Prova na Matemática Escolar, referindo-se, particularmente, à 2ª Fase deste projeto. Fundamentamo-nos em pesquisas que exploram as funções que uma prova pode assumir e as avaliam, no contexto escolar, sob vários aspectos e níveis de generalidade. À luz dos principais resultados desses estudos e do levantamento das concepções sobre prova de alunos adolescentes, realizado na 1a Fase do Projeto, elaboramos uma seqüência de atividades com o intuito de engajá-los nas várias etapas do processo de prova e discutir as condições de transição das provas pragmáticas para as conceituais. Buscamos, neste contexto, explorar outras funções da prova, além da função de verificação e avaliar o papel da ferramenta Microsoft Excel no trabalho empírico dos alunos. A seqüência foi aplicada, em sessões extraclasse, a três duplas de alunos de 15-16 anos de uma escola particular da cidade de Santos-SP, que participaram voluntariamente da experimentação. Como resultado, verificou-se que a interação dos alunos com o computador dinamizou o processo de produção de conjecturas e de validação experimental destas, bem como a observação de propriedades dos objetos manipulados, favorecendo a elaboração de justificativas que vão além das evidências empíricas. Assim, por meio desta abordagem, os alunos tiveram a oportunidade de vivenciar as etapas do processo de prova, apresentando, por meio de raciocínios dedutivos, argumentos que evidenciam a generalidade envolvida nas tarefas propostas

The central objective of this work consists of gives rise to a theoretical reflection on the relationships involving Man and Nature. It constitutes also a dialogue with a previously written paper on the same subject. Both, this work and the corresponding paper, give rise to an educational product consisting of a blog. This emerging product can be applied to several teaching situations for high school and university levels. Formal and informal situations are included. The starting point here concerns the confrontation between a predominantly anthropocentric adoption due to Popper and the deconstruction of it by Lynn Margulis. This deconstruction gives rise to a conflict involving different universes of criteria. In this paper is also explored the possible incommensurability implied by the conceptual universes represented by categories like: dignity, critical discussion and reason on the one hand, and time of evolutionary experience, biochemical versatility and importance of the bacteria for the biota, on the other. This reflection leads to the result according to which both, Margulian deconstruction as well as the deconstruction of the deconstruction of her point of view, do not constitute an overcome of the self reference. Therefore, the dignity and autonomy appear as central categories of this confrontation. Rationality, language and education are emergencies concerning the socio cultural world. This study entails an articulated confluence of the fields of Philosophy, Natural and Social Sciences and Education. Several authors are invited to participate of this dialogue. / Esta dissertação tem como objetivo precípuo ensejar uma reflexão teórica sobre as relações Homem/Natureza. Ela se apresenta em diálogo com um artigo escrito sobre o mesmo tema, mas diferentemente estruturado. A dissertação e o artigo correspondente constituem juntos na base teórica para gerar um produto educacional constituído por um blog, aplicável em situações de ensino concernentes tanto ao ensino médio quanto aos primeiros anos do ensino superior. São contempladas tanto situações de ensino formais quanto informais. A presente reflexão sobre as relações Homem/Natureza parte de um confronto, por nós proposto, entre a adoção preponderantemente antropocêntrica de Popper e a desconstrução desta por Lynn Margulis. Esta desconstrução enseja um conflito entre universos distintos de critérios. São exploradas também as relações de comensurabilidade/incomensurabilidade dos universos conceituais de ambas as adoções como: dignidade, discussão crítica e razão, por um lado, e, tempo de experiência evolutiva, versatilidade bioquímica e importância bacteriana para a biota, por outro. Como um dos resultados importantes desta reflexão, ressalta-se que tanto a desconstrução marguliana quanto a desconstrução da desconstrução desta não podem prescindir da autorreferência antropocêntrica. Portanto, dignidade e autonomia revelam-se como categorias centrais deste confronto. Racionalidade, linguagem e educação são emergências concernentes ao mundo sócio cultural. Este estudo se insere nos campos articulados da Filosofia, das Ciências Naturais e Sociais e da Educação. Para tal, procede-se a uma interlocução com autores de diversificadas lavras intelectuais.

Introduction Digital databases and libraries have for the last 20 years become ubiquitous tools in the philological study of ancient texts. While these databases provide easy access to texts, critical information is often lacking. One example of that is information regarding conjectures and conjectural emendations in the texts. A number of projects in recent years have aimed to collect conjectures in a digital format and present them online, but none have so far been aimed at Ancient Greek philology. To further develop this area of research it is the aim of this thesis to illustrate how conjectures on Ancient Greek literature can be collected and presented in a digital context to fulfil the information needs of philologists. Method Semi structured interviews were conducted with philologists at Uppsala University, University of Oslo and Oxford University. The interviews were tape recorded and the transcripts of the interviews formed the data for analysis. Analysis Qualitative analyses were carried out on the data. To analyse the information needs of the philologists, theoretical approaches found in hermeneutics and information scientific research on the interaction of library professionals and philologists were used. Results It was found that the information needs of philologists varied depending on their professional orientations, e.g. if they were focused on textual criticism, reception studies, ancient or medieval philology. In the interviews it became clear that the use of digital tools varied somewhat between the philologists. The interviews also showed that there are a number of active projects aimed at producing digital critical editions. University and other research libraries are generally where information on proposed conjectures can be found. Conclusion Generally the philologists expressed a need for easier access to the reasonings behind conjectures. Searching for such information is time consuming because it has not been recorded with the same scholarly rigor as other kinds of information. The establishment and online publication of bibliographic records is a first step to amend this need. Current open-source projects aimed at producing digital critical editions can form the basis for further developments in the field. Since research libraries are where information on conjectures can be found, they play an important role in making this information accessible. Further interaction between philology scholars and library professionals is encouraged in order to identify where information can be found and how it can be digitized and made accessible. This is a two years master’s thesis in Library and Information Science.

Das Ziel dieser Arbeit ist die Berechnung der arithmetischen Volumina der Shimuravarietäten vom orthogonalen Typ und der natürlichen Höhen der speziellen Zykel auf diesen. Wir entwickeln, für den Fall guter Reduktion, eine allgemeine Theorie ganzzahliger Modelle von toroidalen Kompaktifizierungen der Shimuravarietäten vom Hodge Typ (sowie des Standardhauptfaserbündels darüber). Dies ermöglicht, unter Verwendung der Theorie der Borcherdsprodukte, das arithmetische Voluminen einer zu einem Gitter L der Diskriminante D assoziierten Shimuravarietät, bis auf log(p) Beiträge zu Primzahlen p mit p^2|4D, zu berechnen. Dies ist eine Verallgemeinerung einer Arbeit von Burgos, Bruinier und Kühn. Die Höhen der speziellen Zykel werden im Falle von Kodimension 1 bis auf log(p)-Beiträge mit p|2D berechnet, sowie unter leichten zusätzlichen Einschränkungen im Falle von Kodimension > 1. The resultierenden Grössen sind spezielle Ableitungswerte gewisser L-Reihen. Im Falle der speziellen Zykel stimmen diese mit speziellen Ableitungswerten gewisser normalisierter Eisensteinreihen überein (zusätzlich, bis auf Beiträge bei unendlich). Dies bestätigt Vermutungen von Bruinier-Kühn, Kudla und anderen. / The overall aim of this thesis is to compute arithmetic volumes of Shimura varieties of orthogonal type and natural heights of the special cycles on them. We develop a general theory of integral models of toroidal compactifications of Shimura varieties of Hodge type (and of its standard principal bundle) for the case of good reduction. This enables us, using the theory of Borcherds products, and generalizing work of Burgos, Bruinier and Kühn, to calculate the arithmetic volume of a Shimura variety associated with a lattice L of discriminant D, up to log(p)-contributions from primes p such that p^2|4D. The heights of the special cycles are calculated in the codimension 1 case up to log(p), p|2D, and with some additional restrictions in the codimension > 1 case. The values obtained are special derivatives of certain L-series. In the case of the special cycles they are equal to special derivatives of Fourier coefficients of certain normalized Eisenstein series (in addition, up to contributions from infinity) in accordance with conjectures of Bruinier-Kühn, Kudla, and others.

Made available in DSpace on 2016-04-27T17:13:02Z (GMT). No. of bitstreams: 1 aguinaldo rama.pdf: 834376 bytes, checksum: 115c94033b3852d2fd9618f3cb19a427 (MD5) Previous issue date: 2005-11-08 / Made available in DSpace on 2016-08-25T17:25:34Z (GMT). No. of bitstreams: 2 aguinaldo rama.pdf.jpg: 1943 bytes, checksum: cc73c4c239a4c332d642ba1e7c7a9fb2 (MD5) aguinaldo rama.pdf: 834376 bytes, checksum: 115c94033b3852d2fd9618f3cb19a427 (MD5) Previous issue date: 2005-11-08 / We present an analysis of three collections of mathematics text books for primary school. The choice of the collections is oriented by the synthesis presented in the guidebook of the Plano Nacional do Livro Didático. The goal of the analysis is to investigate the way the authors approach the integers, mainly the concept of divisibility. Our main focus concerns proof strategies and the use of challenging problem situations. Two other aspects are considered: relations between integers and other mathematical subjects, particularly álgebra and geometry; articulations between old and new contents, and the resulting review of subjects, during which it is expectec that the learners growing maturity is taken into consideration. We verify that one of the collections presents good informal proofs, suitable for this learning level, using a variety of methods; it also properly explores the potencial of problems related to integers. The second collection presents some convincing proofs together with unsuitable ones, while the third one states several properties without exibiting explanation concerns. The last ones provide few problems demanding a greater sophistication of reasoning. The three collections present the subject in 5th and 6th grades, in the context of natural numbers, and no overview is provided after the introduction of negative numbers. The second part of the work is dedicated to middle school. We examine the eleven collections recomended by the guidebook of the Plano Nacional do Livro do Ensino Médio. We analyse the review of the integers at the beggining of the first books of the collections. Generally speaking, the review is superficial; divisibility concepts including negatives is explored only in the context of exercises. Few more elaborated problems are proposed Finally, we suggest actitities for middle scholl relating integers to a variety of themes, as geometry, complex number, polynomials, combinatorial analysis / Apresentamos uma análise de três coleções de livros de matemática do ensino fundamental. Tomamos como referência para a escolha dos livros as sínteses constantes no guia do Plano Nacional do Livro Didático. O objetivo dessa análise é verificar a forma como os autores abordam os números inteiros, em particular o conceito de divisibilidade. Damos maior atenção para dois aspectos: as estratégias adotadas para demonstrações referentes ao assunto, e o uso de situações-problema desafiadoras. Também consideramos dois outros aspectos: articulações entre números inteiros e as demais áreas da matemática, em particular a álgebra e a geometria; articulações entre conteúdos novos e já conhecidos, e as conseqüentes retomadas de temas, nas quais espera-se que o suposto amadurecimento dos estudantes seja considerado. Constatamos que uma das coleções apresenta boas provas informais, adequadas para esse estágio de aprendizagem, usando métodos variados; também explora de modo conveniente o potencial de problemas envolvendo números inteiros. A segunda coleção apresenta algumas demonstrações convincentes, e outras inadequadas; a terceira enuncia diversas propriedades sem preocupação com justificativas. Nessas duas últimas, poucos problemas exigem maior sofisticação de raciocínio. Nas três coleções o assunto é enfocado quase exclusivamente na 5º e na 6º série, no âmbito dos números naturais, não sendo retomado no contexto dos inteiros, após a introdução dos negativos. A segunda parte do trabalho é dedicada ao ensino médio. Consultamos as onze coleções recomendas pelo guia do Plano Nacional do Livro do Ensino Médio. Analisamos a revisão dos inteiros feita no início dos primeiros livros dessas coleções. De modo geral, essa retomada é superficial; o conceito de divisibilidade entre inteiros, incluindo os negativos, pode ser apreciado somente em uns poucos exercícios. Poucos problemas mais elaborados são propostos. Finalizamos com sugestões de atividades para o ensino médio envolvendo números inteiros, em conexão com assuntos variados, tais como: geometria, números complexos, polinômios, análise combinatória

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