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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Matrizes de conexão via o complexo de Morse-Witten / Connection matrices via the Morse-Witten

Lima, Dahisy Valadão de Souza, 1986- 08 May 2010 (has links)
Orientador: Ketty Abaroa de Rezende / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-16T15:34:50Z (GMT). No. of bitstreams: 1 Lima_DahisyValadaodeSouza_M.pdf: 1595993 bytes, checksum: 49a95ad790c477c7d049695a123d9acd (MD5) Previous issue date: 2010 / Resumo: Dada uma variedade suave e fechada M, o complexo de Morse-Witten associado a uma função de Morse f : M ? R e a uma métrica Riemanniana g em M consiste de grupos de cadeia gerados pelos pontos críticos de f e um operador bordo que conta linhas de fluxos isoladas do fluxo gradiente negativo. A homologia do complexo de Morse-Witten é isomorfa à homologia singular de M. Dado um conjunto invariante isolado S, uma matriz de conexão para uma decomposição de Morse de S é uma matriz de homomorfismos entre os índices homológicos de Conley dos conjuntos de Morse. A matriz de conexão é capaz de prover informações dinâmicas sobre um fluxo. De fato, esta matriz pode detectar a existência de órbitas conectantes entre os conjuntos de Morse de S. O complexo de Morse-Witten está relacionado à teoria de matrizes de conexão. Mais precisamente, o operador bordo do complexo de Morse-Witten é um caso especial de matriz de conexão / Abstract: Given a smooth closed manifold M, the Morse-Witten complex associated to a Morse function f : M ? R and a Riemannian metric g on M consists of chain groups generated by the critical points of f and a boundary operator counting isolated flow lines of the negative gradient flow. The homology of the Morse-Witten complex is isomorphic to the singular homology of M. Give a isolated invariant set S, a connection matrix for a Morse decomposition of S is a matrix of homomorphism between the Conley homology indices of Morse sets. The connection matrix is capable of providing dynamical information of a flow. In fact, this matrix can detect the existence of connecting orbits among Morse sets of S: The Morse-Witten complex is related to connection matrices theory. More precisely, the boundary operator of the Morse-Witten complex is a special case of connection matrix / Mestrado / Matematica / Mestre em Matemática
32

Matrizes de conexão para as dinamicas continua e discreta / Connectiion matrices for the continuous and discrete dynamics

Paulo, Naiara Vergian de 15 August 2018 (has links)
Orientador: Ketty Abaroa de Rezende / Dissertação (mestrado) - Universidade Esstadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-15T16:45:11Z (GMT). No. of bitstreams: 1 Paulo_NaiaraVergiande_M.pdf: 3206526 bytes, checksum: 8b9412f659496d0b15142c86dfe55a5d (MD5) Previous issue date: 2010 / Resumo: O objetivo deste trabalho é apresentar a matriz de conexão, estabelecendo um paralelo entre as abordagens contínua e discreta. O índice homológico de Conley, principal elemento para a definição da matriz de conexão, assume formas distintas quando lidamos com fuxos ou com aplicações contínuas. Tal índice trata-se apenas de um espaço vetorial graduado no caso contínuo, enquanto no caso discreto toma a forma de um par que consiste de um espaço vetorial graduado junto com um isomorfismo. Como consequência, a matriz de conexão para uma decomposição de Morse é definida diferentemente quando consideramos sistemas dinâmicos contínuos ou discretos. No primeiro caso, a matriz de conexão é uma matriz de aplicações lineares entre os índices contínuos homológicos de Conley dos conjuntos de Morse que codifica uma trança de espaços vetoriais graduados, conhecida como trança do índice contínuo homológico. Já no segundo caso, a matriz de conexão é um par de matrizes que têm como entradas aplicações lineares definidas entre os índices discretos homológicos de Conley dos conjuntos de Morse e, agora, este par de matrizes codifica uma trançaa de espaços vetoriais graduados com isomorfismos, chamada trança do índice discreto homológico. Apesar do índice homológico de Conley e da matriz de conexão serem elementos puramente algébricos, ambos são capazes de fornecer informações dinâmicas sobre um fuxo e mais ainda sobre uma aplicação contínua. Especificamente, estes elementos podem detectar a existência de órbitas de conexão entre conjuntos de Morse de um conjunto invariante isolado e exemplos desta situação são apresentados neste trabalho / Abstract: The goal of this work is to present the connection matrix by establishing a parallel between the continuous and discrete settings. The homological Conley index, the main element in the definition of the connection matrix, has a diferent form for flows or continuous maps. This index is a graded vector space in the continuous case whereas in the discrete case it takes the form of a pair consisting of a graded vector space together with an isomorphism. Consequently, the connection matrix for a Morse decomposition is defined diferently when we consider continuous or discrete dynamical systems. In the prior case, the connection matrix is a matrix of linear maps between the continuous Conley homology indices of Morse sets which codes the information of a graded vector space braid known as the continuous homology index braid. In the latter case, the connection matrix is a pair of matrices where the entries in both case are linear maps de?ned between the discrete Conley homology indices of Morse sets and, in this setting, this pair of matrices codes the information of a graded vector space braid with isomorphism known as discrete homology index braid. Although the Conley homology index and the connection matrix constitute purely algebraic elements, they are capable of providing dynamical information of a fow and of a continuous map. More precisely, these elements can detect the existence of connecting orbits among Morse sets of an isolated invariant set and examples of this situation are presented in this work. / Mestrado / Sistemas Dinamicos Topologicos / Mestre em Matemática
33

O indice de Conley para campos de vetores descontinuos / The Conley index for discontinuous vector fields

Casagrande, Rogério, 1971- 23 April 2008 (has links)
Orientador: Ketty Abaroa de Rezende / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-10T21:23:33Z (GMT). No. of bitstreams: 1 Casagrande_Rogerio_D.pdf: 791160 bytes, checksum: 010eb0b4b4c51c71ac7df0e6a9c2ad1e (MD5) Previous issue date: 2008 / Resumo: O índice de Conley é um invariante topológico usado na análise do comportamento qua¬litativo de sistemas dinâmicos. Inicialmente a teoria foi desenvolvida para fluxos contínuos em espaços de dimensão finita e posteriormente estendida para o caso discreto. Neste tra¬balho, apresentamos uma teoria do índice de Conley para uma classe de campos vetoriais descontínuos, com descontinuidade de primeira espécie. Campos vetoriais descontínuos são freqüentes em varias áreas da Ciência e Engenharia e podem ser expressos por sistemas suaves por partes em uma variedade n-dimensional compacta M. Considere uma estratificação de Whitney de M e seja Z um campo descontínuo em M, onde a região de descohtinuidade, D, é o estrato de codimensão um. Mostramos a existência de um D-par índice (N, L) e sua invariância quanto ao tipo de homotopia do espaço N quocientado por L. Desta forma o D-índice de Conley fica bem definido e apresentamos alguns exemplos de seu cálculo. Utilizamos o D-Índice de ConIey para exibirmos condições suficientes para a existência de pontos de bifurcação em uma família a um parâmetro de campos descontínuos. Apresen¬tamos uma teoria de continuação para D-grafos de Lyapunov associado à classe de campos descontínuos / Abstract: The Conley index is a used as a topological invariant in the analysis of the qualitative behavior of dynamical systems. lnitially the theory was developed for continuous flows in finite dimensional spaces and later extended to the infinite dimensional setting as well as to the discrete case. ln this work, we present a Conley index theory for a class of discontinuous vectar fields, with discontinuity of the first kind. Discontinuous vector fields are frequent in several areas of Science and Engineering and can be expressed as piecewise differentiable vector fields on an n-dimensional compact manifold, M. We consider a Whitney sttatification of M and a discontinuous vector field Z on M, where the region of discontinuity, D, is the strata of codimension one. We show the existence of a D-index pair (N, L) and prove that the quotienL space N/L independs on the pair chosen, thus defining the D-Conley index as the homotopy type of this quotient space. We present some examples of its calculation. We also use the D-Conley index to show sufficient conditions for the existence of bifurcation points in a one parameter family of discontinuous vector fields. We also present a theory of continuation for Lyapunov D-graphs associated to this class of discontinuous vector fields / Doutorado / Geometria e Topologia / Doutor em Matemática
34

A teoria do índice de Conley discreta para conjuntos básicos zero-dimensionais / Discrete Conley's index theory for zero-dimensional basic sets

Villapouca, Mariana Gesualdi, 1984- 06 July 2013 (has links)
Orientador: Ketty Abaroa de Rezende / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-23T01:07:46Z (GMT). No. of bitstreams: 1 Villapouca_MarianaGesualdi_D.pdf: 1687322 bytes, checksum: 9557d400e3eadbf12a6a305e0219b2cb (MD5) Previous issue date: 2013 / Resumo: Este trabalho tem como foco o estudo do índice de Conley discreto e do par de matrizes de conexão para difeomorfismos fitted Smale em variedades compactas. Foi estabelecido um teorema que apresenta o cálculo do índice de Conley de conjuntos básicos zero - dimensionais usando a informação dinâmica contida nas matrizes de estrutura associadas. A classificação do índice de Conley homológico reduzido de conjuntos básicos zero - dimensionais, utilizando a sua forma de Jordan real foi apresentada. Estabelecemos uma caracterização de pares de matrizes de conexão para decomposições de Morse em conjuntos básicos zero - dimensionais para uma classe de difeomorfismos fitted Smale / Abstract: Our focus in this thesis was on the further development of the discrete Conley index theory with the aim of addressing questions on the pair of connection matrices for fitted Smale diffeomorphisms on compact manifolds. A theorem was established where the computation of the discrete Conley index for zero dimensional basic sets was given with respect to the dynamical information contained in the associated structure matrices. A classification of the reduced homology Conley index of a zero dimensional basic set in terms of its Jordan real form is presented. A characterization of a pair of connection matrices for a Morse decomposition of zero dimensional basic sets of a class of fitted Smale diffeomorphisms is established / Doutorado / Matematica / Doutora em Matemática
35

Une méthode topologique pour la recherche d'ensembles invariants de systèmes continus et à communtation / A topological method for finding invariant sets of continuous and switched systems

Mohamed, Sameh 17 October 2016 (has links)
On cherchera dans cette thèse à prouver l'existence d'ensembles invariants pour des systèmes continus et l'existence de noyaux de viabilité pour des systèmes à commutation (dépendant de l'espace ou du temps) dans des sous-ensembles de l'espace des phases. Ces objets sont des plus importants dans la théorie des systèmes dynamiques, ils peuvent être décrits de manière informelle comme étant des ensembles qui, lorsque le système dynamique y entre, il y restera à tout jamais. Pour prouver l'existence de tels ensembles on utilisera une propriété topologique dite propriété (ou principe) de Wazewski. On présentera alors une méthode effective pour pouvoir appliquer ce principe à des systèmes continus premièrement. Puis nous généraliserons cette première méthode pour pouvoir la rendre applicable aussi à des systèmes à commutation. / We aim at proving the existence of invariants sets for continuous systems and viability kernels for (time-dependent and state-dependent) switched systems in compact subsets of the phase space. They are of the most important objects of dynamical systems theory. They can be described informally by saying that they are subsets such that, if the dynamical system goes inside, it will remain inside forever. For proving the existence of such sets we will use a topological property named the Wazewski property (or principle).We will firstly present an effective method for applying this principle for continuous systems and then we will generalize this first method in order to make it applicable also for switched systems.
36

Quasiparticles in the Quantum Hall Effect

Kailasvuori, Janik January 2006 (has links)
<p>The fractional quantum Hall effect (FQHE), discovered in 1982 in a two-dimensional electron system, has generated a wealth of successful theory and new concepts in condensed matter physics, but is still not fully understood. The possibility of having nonabelian quasiparticle statistics has recently attracted attention on purely theoretical grounds but also because of its potential applications in topologically protected quantum computing.</p><p>This thesis focuses on the quasiparticles using three different approaches. The first is an effective Chern-Simons theory description, where the noncommutativity imposed on the classical space variables captures the incompressibility. We propose a construction of the quasielectron and illustrate how many-body quantum effects are emulated by a classical noncommutative theory.</p><p>The second approach involves a study of quantum Hall states on a torus where one of the periods is taken to be almost zero. Characteristic quantum Hall properties survive in this limit in which they become very simple to understand. We illustrate this by giving a simple counting argument for degeneracy 2<i>n</i><sup>-1</sup>, pertinent to nonabelian statistics, in the presence of 2<i>n</i> quasiholes in the Moore-Read state and generalise this result to 2<i>n</i>-<i>k</i> quasiholes and <i>k </i>quasielectrons.</p><p>In the third approach, we study the topological nature of the degeneracy 2<i>n</i><sup>-1</sup> by using a recently proposed analogy between the Moore-Read state and the two-dimensional spin-polarized p-wave BCS state. We study a version of this problem where one can use techniques developed in the context of high-<i>T</i>c superconductors to turn the vortex background into an effective gauge field in a Dirac equation. Topological arguments in the form of index theory gives the degeneracy 2<i>n</i><sup>-1</sup> for 2<i>n</i> vortices.</p>
37

Quasiparticles in the Quantum Hall Effect

Kailasvuori, Janik January 2006 (has links)
The fractional quantum Hall effect (FQHE), discovered in 1982 in a two-dimensional electron system, has generated a wealth of successful theory and new concepts in condensed matter physics, but is still not fully understood. The possibility of having nonabelian quasiparticle statistics has recently attracted attention on purely theoretical grounds but also because of its potential applications in topologically protected quantum computing. This thesis focuses on the quasiparticles using three different approaches. The first is an effective Chern-Simons theory description, where the noncommutativity imposed on the classical space variables captures the incompressibility. We propose a construction of the quasielectron and illustrate how many-body quantum effects are emulated by a classical noncommutative theory. The second approach involves a study of quantum Hall states on a torus where one of the periods is taken to be almost zero. Characteristic quantum Hall properties survive in this limit in which they become very simple to understand. We illustrate this by giving a simple counting argument for degeneracy 2n-1, pertinent to nonabelian statistics, in the presence of 2n quasiholes in the Moore-Read state and generalise this result to 2n-k quasiholes and k quasielectrons. In the third approach, we study the topological nature of the degeneracy 2n-1 by using a recently proposed analogy between the Moore-Read state and the two-dimensional spin-polarized p-wave BCS state. We study a version of this problem where one can use techniques developed in the context of high-Tc superconductors to turn the vortex background into an effective gauge field in a Dirac equation. Topological arguments in the form of index theory gives the degeneracy 2n-1 for 2n vortices.
38

Surface Topological Analysis for Image Synthesis

Zhang, Eugene 09 July 2004 (has links)
Topology-related issues are becoming increasingly important in Computer Graphics. This research examines the use of topological analysis for solving two important problems in 3D Graphics: surface parameterization, and vector field design on surfaces. Many applications, such as high-quality and interactive image synthesis, benefit from the solutions to these problems. Surface parameterization refers to segmenting a 3D surface into a number of patches and unfolding them onto a plane. A surface parameterization allows surface properties to be sampled and stored in a texture map for high-quality and interactive display. One of the most important quality measurements for surface parameterization is stretch, which causes an uneven sampling rate across the surface and needs to be avoided whenever possible. In this thesis, I present an automatic parameterization technique that segments the surface according to the handles and large protrusions in the surface. This results in a small number of large patches that can be unfolded with relatively little stretch. To locate the handles and large protrusions, I make use of topological analysis of a distance-based function on the surface. Vector field design refers to creating continuous vector fields on 3D surfaces with control over vector field topology, such as the number and location of the singularities. Many graphics applications make use of an input vector field. The singularities in the input vector field often cause visual artifacts for these applications, such as texture synthesis and non-photorealistic rendering. In this thesis, I describe a vector field design system for both planar domains and 3D mesh surfaces. The system provides topological editing operations that allow the user to control the number and location of the singularities in the vector field. For the system to work for 3D meshes surface, I present a novel piecewise interpolating scheme that produces a continuous vector field based on the vector values defined at the vertices of the mesh. I demonstrate the effectiveness of the system through several graphics applications: painterly rendering of still images, pencil-sketches of surfaces, and texture synthesis.
39

Théorie de l'indice pour les familles d'opérateurs G-transversalement elliptiques / Index theory for families of G-transversally elliptic operators

Baldare, Alexandre 16 February 2018 (has links)
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.
40

Lyapunov graph in the study of Smale flows and Morse-Novikov flows = Grafo de Lyapunov no estudo dos fluxos de Smale e fluxos de Morse-Novikov / Grafo de Lyapunov no estudo dos fluxos de Smale e fluxos de Morse-Novikov

Espiritu Ledesma, Guido Gerson, 1985- 24 August 2018 (has links)
Orientador: Ketty Abaroa de Rezende / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-24T17:12:31Z (GMT). No. of bitstreams: 1 EspirituLedesma_GuidoGerson_D.pdf: 1229937 bytes, checksum: 00f2d538b5b2a2c4147d828351f4ef16 (MD5) Previous issue date: 2014 / Resumo: Neste trabalho, usamos os grafos de Lyapunov como uma ferramenta combinat{\'o}ria para obter classifica\c{c}{\~o}es completas de fluxos Smale sobre $\ss$ e fluxos Morse-Novikov sobre superf{\'i}cies orient{\'a}veis e n{\~a}o orient{\'a}veis. Esta classifica\c{c}{\~a}o consiste em obter condi\c{c}{\~o}es necess{\'a}rias e suficientes que devem ser satisfeitas por um grafo de Lyapunov abstrato de forma a ser associado a um fluxo Smale sobre $\ss$ ou um fluxo Morse-Novikov sobre uma superf{\'i}cie respectivamente. Assim nesta tese de doutorado obtemos os seguintes resultados: \begin{enumerate} \item As condições locais que devem ser satisfeitas por cada vértice do grafo de Lyapunov, assim como as condições globais que devem ser satisfeitas pelos grafos para estarem associados a um fluxo Smale sobre $\ss$ ou a um fluxo Morse-Novikov sobre uma superfície s{\~a}o determinadas. \item A realização destes grafos abstratos sujeita {\'a}s condições determinadas acima, como fluxos Smale sobre $\ss$ ou fluxos Morse-Novikov sobre superfícies respectivamente, são obtidas. \end{enumerate} / Abstract: In this work Lyapunov graphs are used as a combinatorial tool in order to obtain a complete classification of Smale flows on $\ss$ and Morse-Novikov flows on orientable and non-orientable surfaces. This classification consists in determining necessary and sufficient conditions that must be satisfied by an abstract Lyapunov graph so that it is associated to a Smale flow on $\ss$ or to a Morse-Novikov flow on a surface respectively.\\ In summary in this doctoral thesis we obtain the following results: \begin{enumerate} \item The local conditions that must be satisfied by each vertex on a Lyapunov graph is determinated as well as the global conditions on the graph in order for it to be associated to a Smale flow on $\ss$ or a Morse-Novikov flow on a surface. \item The realization of these graphs subject to the conditions found above as Smale flows on $\ss$ or as Morse-Novikov flows on surfaces respectively is obtained. \end{enumerate} / Doutorado / Matematica / Doutor em Matemática

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