Generalized geometry of type B_n is the study of geometric structures in T+T^*+1, the sum of the tangent and cotangent bundles of a manifold and a trivial rank 1 bundle. The symmetries of this theory include, apart from B-fields, the novel A-fields. The relation between B_n-geometry and usual generalized geometry is stated via generalized reduction. We show that it is possible to twist T+T^*+1 by choosing a closed 2-form F and a 3-form H such that dH+F²=0. This motivates the definition of an odd exact Courant algebroid. When twisting, the differential on forms gets twisted by d+Fτ+H. We compute the cohomology of this differential, give some examples, and state its relation with T-duality when F is integral. We define B_n-generalized complex structures (B_n-gcs), which exist both in even and odd dimensional manifolds. We show that complex, symplectic, cosymplectic and normal almost contact structures are examples of B_n-gcs. A B_n-gcs is equivalent to a decomposition (T+T^*+1)_ℂ= L + L + U. We show that there is a differential operator on the exterior bundle of L+U, which turns L+U into a Lie algebroid by considering the derived bracket. We state and prove the Maurer-Cartan equation for a B_n-gcs. We then work on surfaces. By the irreducibility of the spinor representations for signature (n+1,n), there is no distinction between even and odd B_n-gcs, so the type change phenomenon already occurs on surfaces. We deal with normal forms and L+U-cohomology. We finish by defining G²₂-structures on 3-manifolds, a structure with no analogue in usual generalized geometry. We prove an analogue of the Moser argument and describe the cone of G²₂-structures in cohomology.

Le problème de l'indice est de calculer l'indice d'un opérateur elliptique en termes topologiques. Ce problème fut résolu par M. Atiyah et I. Singer en 1963 dans "The index of elliptic operators on compact manifolds". Quelques années plus tard, ces auteurs ont fourni une nouvelle preuve dans "The index of elliptic operators I" permettant plusieurs généralisations et applications. La première est la prise en compte de l'action d'un groupe compact G, dans ce cadre on obtient une égalité dans l'anneau des représentations de G. Par la suite ils ont généralisé ce résultat au cadre des familles d'opérateurs elliptiques paramétrées par un espace compact dans "The index of elliptic operators IV", ici l'égalité vit dans la K-théorie de l'espace paramétrant la famille.Une autre généralisation importante est celle des opérateurs transversalement elliptiques par rapport à l'action d'un groupe G, c'est-à-dire elliptiques dans le sens transverse aux orbites de l'action d'un groupe sur une variété. Cette classe d'opérateurs a été étudié pour la première fois dans le cadre d'un opérateur P agissant sur une variété M par M. Atiyah (et I. Singer) dans "Elliptic operators and compact groups", en 1974. Dans cet article l'auteur définit une classe indice et montre qu'elle ne dépend que de la classe du symbole en K-théorie. Il montre ensuite qu'elle vérifie différents axiomes : action libre, multiplicativité et excision. Ces différents axiomes permettent alors de ramener le calcul de l'indice à un espace euclidien muni de l'action d'un tore. Par la suite, cette classe d'opérateurs a été étudier du point de vue de la K-théorie bivariante par P. Julg [1982] et plus récemment dans le cadre des actions propres sur une variété non compacte par G. Kasparov [2016].Dans cette thèse, nous nous intéressons aux familles d'opérateurs G-transversalement elliptiques. Nous définissons une classe indice en K-théorie bivariante de Kasparov. Nous vérifions qu'elle ne dépend que de la classe du symbole de la famille en K-théorie. Nous montrons que notre classe indice vérifie les propriétés d'action libre, de multiplicativité et d'excision espérées en K-théorie bivariante. Nous montrons ensuite un théorème d'induction et de compatibilité avec les applications de Gysin. Ces derniers théorèmes permettent de ramener le calcul de l'indice au cas d'une famille triviale pour l'action d'un tore comme dans le cadre d'un seul opérateur sur une variété. Nous démontrons ensuite qu'on peut associer à cette classe indice un caractère de Chern à coefficients distributionnels sur G à valeurs dans la cohomologie de de Rham de l'espace paramétrant lorsque c'est une variété. Pour ce faire, nous utilisons l'homologie locale de M. Puschnigg [2003] et une technique de M. Hilsum et G. Skandalis [1987]. Par la suite, nous nous intéressons aux formules de Berline et Vergne dans ce cadre. Avant de passer aux formules générales pour une famille d'opérateurs G-transversalment elliptiques, on commence par regarder si on obtient les mêmes formules dans le cadre elliptique. On montre alors des égalités similaires à celles obtenues par N. Berline et M. Vergne [1985] dans le cadre d'un opérateur elliptique G-invariant. Dans un dernier chapitre, on montre la formule de Berline-Vergne dans le cadre des familles d'opérateurs G-transversalement elliptiques. On utilise ici la formule de Berline-Vergne pour un opérateur G-transversalement elliptique et les différentes techniques mises en place dans les chapitres précédents. / The index problem is to calculate the index of an elliptic operator in topological terms. This problem was solved by M. Atiyah and I. Singer in 1963 in "The index of elliptic operators on compact manifolds". Few years later, these authors have given a new proof in "The index of elliptic operators I" allowing several generalizations and applications. The first is taking into account of the action of a compact group G, in this frame they obtain an equality in the ring of the representations of G. Later they generalized this result to the framework of the families of elliptic operators parameterized by a compact space in "The index of elliptic operators IV", here equality lives in the K-theory of the space of parameter.Another important generalization is the transversely elliptic operators with respect to a group action, that is to say, elliptic in the transverse direction to the orbits of a group action on a manifold. This class of operators has been studied for the first time by M. Atiyah (and I. Singer) in "Elliptic operators and compact groups", in 1974. In this article the author defines an index class and shows that it depends only on the symbol class in K-theory. Then he shows that it verifies different axioms: free action, multiplicativity and excision. These different axioms allows to reduce the calculation of the index to an Euclidean space equipped with an action of a torus. Next, this class of operators has been studied from the point of view of bivariant K-theory by P. Julg [1982] and more recently in the context of proper action on a non-compact manifolds by G. Kasparov [2016].In this thesis, we are interested in families of G-transversely elliptic operators. We define an index class in Kasparov bivariant K-theory. We verify that it depends only on the class of the symbol of the family in K-theory. We show that our index class satisfies the expected free action, multiplicativity and excision properties in bivariant K-theory. We then show a theorem of induction and compatibility with Gysin maps. These last theorems allows to reduce the calculation of the index to the case of a trivial family for the action of a torus as in the framework of a single operator on a manifold. We then prove that we can associate to this index class a Chern character with distributional coefficients on G with values ​​in the de Rham cohomology of the parameter space when it is a manifold. To do this, we use the bivariant local cyclic homology of M. Puschnigg [2003] and a technique of M. Hilsum and G. Skandalis [1987].Before treating the general framework of families of G-transversely elliptic operators, we look at the elliptic case. We show that the expected formulas are true in this context. In the last chapter, we show the Berline-Vergne formula in the context of families of G-transversely elliptic operators. We use here the Berline-Vergne formula for a G-transversely elliptic operator and the different methods used in the previous chapters.

Les grassmanniennes symplectiques impaires sont une famille d'espaces quasi-homogènes très proches des grassmanniennes symplectiques de par leur construction et leurs propriétés. Dans ce travail, j'étudie leur cohomologie classique et quantique. Pour les grassmanniennes symplectiques impaires de droites, j'obtiens une règle de Pieri quantique ainsi qu'une présentation de l'anneau de cohomologie quantique. J'en déduis la semi-simplicité de cet anneau et je détermine une collection exceptionnelle complète pour la catégorie dérivée, ce qui me permet de vérifier pour cet exemple une conjecture de Dubrovin. Dans le cas général, je démontre un principe quantique-classique pour certains invariants de Gromov-Witten de degré un. Sous réserve de l'énumérativité des invariants de degré supérieur, je prouve que la règle de Pieri quantique est entièrement déterminée par le calcul des invariants de degré un. / Odd symplectic Grassmannians are a family of quasi-homogeneous spaces that are closely related to symplectic Grassmannians by their construction and properties. The goal of this work is to study their classical and quantum cohomology. For odd symplectic Grassmannians of lines, I obtain a quantum Pieri rule and a presentation of the quantum cohomology ring. I prove the semisimplicity of this ring and determine a full exceptional collection for the derived category, which enables me to check a conjecture of Dubrovin in this example. In the general case, I prove a quantum-to-classical principle for some degree one Gromov-Witten invariants. Assuming higher-dimensional Gromov-Witten invariants are enumerative, I conclude that the quantum Pieri rule is entirely determined by the knowledge of degree one invariants.

Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-08-11T12:32:04Z No. of bitstreams: 1 arquivototal.pdf: 604214 bytes, checksum: ba88d16062ebf0bc144fe2cd43359547 (MD5) / Made available in DSpace on 2017-08-11T12:32:05Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 604214 bytes, checksum: ba88d16062ebf0bc144fe2cd43359547 (MD5) Previous issue date: 2016-03-09 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The connection between the theory of local cohomology and the theory of secondary representation and attached prime ideals is exposed in the work of R. Y. Sharp and I. G. Macdonald and it displayed itself as very prolific since the statement of various conditions of vanishing and non-vanishing for some local cohomology modules. In this work we show that, in some conditions, the (generalised) Matlis dual DR (M ) of a module M over a semi-local ring R is Artinian, hence representable. Under the same conditions we show that AttR (DR (M )) = Ass(M ). We also describe the set of attached primes of co-localisations of modules and of some local cohomology modules. The use for the latter is, as an example, to describe the set of attached primes of the top local cohomology module Ha dim(R)(R) as the set of prime ideals of R which satisfy the condition of Lichtenbaum–Hartshorne Vanishing Theorem. / A conexão entre a teoria de cohomologia local e a teoria de representação secundária e ideais primos anexados foi exposta nos trabalhos de R. Y. Sharp e I. G. Macdonald e mostrou-se bastante prolı́fica, uma vez que foram estabelecidas condições de anulamento e não anulamento de determinados módulos de cohomologia local. Neste trabalho, provamos que, para determinadas condições, o dual de Matlis (generalizado) de um módulo M , DR (M ), sobre um anel semi-local R, é Artiniano e, portanto, representável. Sob estas condições, mostramos que AttR DR (M ) = AssM . Além disso, descrevemos os conjuntos de primos anexados de alguns módulos de cohomologia local e módulos via co-localização. Por exemplo, mostramos que o conjunto dos ideais primos anexados do módulo de cohomologia local Ha dim(R) (R) é justamente o conjunto de ideais primos de R que satisfazem a condição do Teorema de Anulamento de Lichtenbaum–Hartshorne.

Made available in DSpace on 2014-06-11T19:30:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-31Bitstream added on 2014-06-13T19:19:04Z : No. of bitstreams: 1 cellini_cp_me_sjrp.pdf: 781641 bytes, checksum: 70ed1b385d132f8255370c0014be09b4 (MD5) / Neste trabalho são abordados alguns aspectos da teoria de dualidade. Ele pode ser dividido em três partes principais. Na primeira demonstramos o teorema de Dualidade de Poincaré para variedades (sem bordo) orientáveis. Para tanto, fez-se necessário o uso do limite direto e cohomologia com suporte compacto. Na segunda definimos grupos de dualidade, em particular, grupo de dualidade de Poincaré, apresentamos alguns resultados e observações sobre a relação existente entre tais grupos e os grupos fundamentais de variedades asféricas fechadas, que é ainda um problema em aberto. Finalmente, alguns resultados envolvendo invariantes cohomológicos ends e grupos de dualidade são apresentados. / In this work we consider some aspects of duality theory. It can be divided in three principal parts. In the first we prove the Poincaré Duality theorem for orientable manifolds (without boundary). For that, it is necessary the use of the direct limit and cohomology with compact supports. In the second part we de¯ne duality groups, in particular, Poincaré duality groups, we introduce some results and observations about the relationship between such groups and fundamental groups of aspherical closed manifolds, that still is an open problem. Finally, some results envolving the cohomological invariant ends and duality groups are presented.

nvestigando a estrutura dos sistemas elementares com simetria de Poincaré em 1 + 1 dimensões, devemos considerar o problema da eliminação das anomalias clássicas, que têm origem no segundo grupo de cohomologia não-trivial deste grupo dinâmico, gerando um termo de Wess-Zumino na ação da partícula relativística. Efetuamos a classificação geral de todos os sistemas elementares em 1 + 1 dimensões, em termos de co-órbitas, mostrando que existe um simplectomorfismo entre o espaço de fase reduzido da partícula e uma determinada co-órbita na álgebra de Lie dual à de Poincaré estendida. / While researching the structure of elementar systems with Poincaré symmetry in 1+1 dimensions, we must be concerned about the problem of elimination of the classical anomalies, which arise from the non-trivial second cohomology group of this dynamical group, generating a Wess-Zumino term in the relativistic particle action. We classify all elementary systems in 1+1 dimensions in terms of co-orbits, showing that there is a symplectomorphism between the reduced phase space of the particle and a certain co-orbit in the Lie algebra dual to the extended Poincaré one.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The purpose of this dissertation is to introduce the notion of local cohomology as well as some of its applications. Initially, we performed a brief review on the main homological tools used in this work, such as: homology of a complex, isomorphism of complexes, injective resolutions, derived functors, etc. Next, we detail properties of the injective modules in the context of Noetherian rings. Finally, we present di erent ways of de ning local cohomology and we show how this notion is used to investigate the arithmetical rank of an ideal. / O objetivo dessa dissertação é introduzir a noção de cohomologia local bem como algumas de suas aplicações. Inicialmente, realizamos um breve apanhado sobre as principais noções homológicas utilizadas no trabalho, tais como: homologia de um complexo, isomorfismo de complexos, resoluções injetivas, funtores derivados, etc. Em seguida, detalhamos propriedades dos módulos injetivos no contexto dos anéis Noetherianos. Finalmente, apresentamos formas variadas de definir cohomologia local e mostramos como essa noção é utilizada para investigar o posto aritmético de um ideal.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / David Mumford introduced the concept of regularity of a coherent beam into the projective space in terms of local cohomology, generalizing a classic argument of Castelnuovo. In this dissertation under view of commutative algebra, we will introduce the concept of regularity of finitely generated graduated modules on the ring of polynomials. First, we perform a preliminary study on dimension theory and especially on Hilbert’s function. We also studied the basics of Cohen- Macaulay modules, properties of Betti’s graduated numbers, and the local cohomology functors. In the main chapter, we define the regularity of Castelnuovo-Mumford using the free resolution shifts. Soon after, we show that the definition of regularity can be given in terms of local cohomology, with emphasis on the cases of Artinian and Cohen-Macaulay modules. / David Mumford introduziu o conceito de regularidade de um feixe coerente no espac¸o projetivo em termos de cohomologia local, generalizando um argumento cl´assico de Castelnuovo. Nessa dissertac¸ ˜ao sob a vis˜ao da ´algebra comutativa, introduziremos o conceito de regularidade de m´odulos graduados finitamente gerados sobre o anel de polinˆomios. Primeiramente realizamos um estudo preliminar sobre teoria da dimens˜ao e em especial sobre a func¸ ˜ao de Hilbert. Tamb´em estudamos noc¸ ˜oes b´asicas em m´odulos Cohen-Macaulay, propriedades dos n´umeros graduados de Betti e dos funtores de cohomologia local. No cap´ıtulo principal, definimos a regularidade de Castelnuovo-Mumford utilizando os shifts de resoluc¸ ˜oes livres. Logo ap´os, mostramos que a definic¸ ˜ao de regularidade pode ser dada em termos de cohomologia local, dando ˆenfase aos casos de m´odulos Artinianos e Cohen-Macaulay. / São Cristóvão, SE

Dada uma ação isométrica livre do grupo binário tetraedral G sobre esferas de dimensão ímpar, obtemos uma decomposição celular finita explícita para as formas espaciais esféricas tetraedrais, fazendo uso do conceito de região (ou domínio) fundamental. A estrutura celular deixa explícita uma descrição do complexo de cadeias sobre o grupo G. Como aplicações, utilizamos o complexo de cadeias e a interpretação geométrica do produto cup para calcular o anel de cohomologia da forma espacial esférica tetraedral em dimensão três, e também calculamos a torção de Reidemeister destes espaços para uma determinada representação de G / Given a free isometric action of a binary tetrahedral group G on odd dimensional spheres, we obtain an explicit finite cellular decomposition of the tetrahedral spherical space forms, using the concept of fundamental domain. The cellular structure gives an explicit description of the associated cellular chain complex over the group G. As applications we use the chain complex and the geometric interpretation of the cup product to calculate the cohomology ring of the tetrahedral spherical space form in three dimension, and also compute the Reidemeister torsion of these spaces for a determined representation of G

Neste trabalho procuramos realizar uma apresentação autocontida sobre os conceitos da teoria algébrica de formas quadráticas e sobre os anéis graduados que surgiram no desenvolvimento desta teoria. Iniciamos procurando esclarecer o sentido da equivalência entre as várias acepções do conceito de forma quadrática. Após a apresentação de ingredientes e resultados geométricos, fazemos um extrato da teoria dos anéis de Witt, conceito que originou a moderna teoria algébrica de formas quadráticas. Disponibilizamos os elementos fundamentais para a formulação das teorias de cohomologia, nos concentrado no desenvolvimento da teoria de cohomologia profinita e, sobretudo, galoisiana. Descrevemos os funtores K0, K1 e K2 da K-teoria clássica e também a K-teoria de Milnor, que é mais adequada para formular questões sobre formas quadráticas. Finalizamos o trabalho com a apresentação de alguns conceitos da Teoria dos Grupos Especiais, uma codificação em primeira-ordem da teoria algébrica das formas quadráticas e exemplificamos sua importância, fornecendo um extrato da prova realizada por Dickmann-Miraglia da conjectura de Marshall sobre assinaturas, que se baseia fortemente nesta teoria. / In this work I try to provide a self-contained presentation on the concepts of algebraic theory of quadratic forms and on the graded rings that have emerged in the development of this theory. I started trying to clarify the meaning of \"equivalence\"between the various meanings of the concept of quadratic form. After the presentation of geometrical ingredients and results, we make an extract of the theory of Witt rings, a concept that originated the modern algebraic theory of quadratic forms. It is provided the key elements for the formulation of cohomology theories, focusing on the development of profinite cohomology theory and, especially, on galoisian cohomology. Are described the functors K0, K1 and K2 of classical K-theory and also the Milnor K-theory, which is more appropriate to formulate questions about quadratic forms. The dissertation is finished with the presentation of some concepts of the Theory of Special Groups, a first-order encoding of algebraic theory of quadratic forms, and with an example its importance by providing an extract of proof by Dickmann-Miraglia of the Marshalls conjecture on signatures, which relies heavily on this theory.