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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.
11

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.
12

Índice de Conley para atratores de inclusão diferencial / Conley index for attractors of differential inclusions

Queiroz, Lenison Alves de 20 August 2018 (has links)
Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-09-21T12:14:18Z No. of bitstreams: 2 Dissertação - Lenison Alves de Queiroz - 2018.pdf: 2458759 bytes, checksum: 2c5c2eaaeddd81877e21434dae197d8e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-09-24T11:11:13Z (GMT) No. of bitstreams: 2 Dissertação - Lenison Alves de Queiroz - 2018.pdf: 2458759 bytes, checksum: 2c5c2eaaeddd81877e21434dae197d8e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-09-24T11:11:13Z (GMT). No. of bitstreams: 2 Dissertação - Lenison Alves de Queiroz - 2018.pdf: 2458759 bytes, checksum: 2c5c2eaaeddd81877e21434dae197d8e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-08-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present work deals with mathematical themes called Conley’s theory, differential inclu- sions and Morse theory inserted in this variant is the topological invariant for the region of discontinuity, the Conley index of discontinuous vector fields, where the discontinuities are concentrated on a surface. With this invariant it is possible to predict bifurcation results, as well as results of regularization of the discontinuous field. In Conley’s Theory, one doesn’t investigate only a single invariant set in a system; on the contrary, it is a decomposition of an invariant set into several “smaller” invariant subsets along with the orbits that connect these subsets. The methodology adopted for the research was based on the deductive analy- sis, a method that allowed the determination of the Conley index using tools of differential inclusions, index-pair and Morse theory to arrive at the determination of the homological in- dex. / O presente trabalho trata de temas da matemática denominados a teoria de Conley, inclusões diferenciais e teoria de Morse inserido nesta variante encontra-se o invariante topológico pa- ra a região de descontinuidade, o índice de Conley de campos de vetores descontínuos, onde as descontinuidades estão concentradas numa superfície. Com este invariante é possível pre- ver resultados de bifurcação, bem como resultados de regularização de campos descontínuos. Na Teoria de Conley, não se investiga somente um único conjunto invariante em um siste- ma, pelo contrário, trata-se de uma decomposição de um conjunto invariante em vários sub- conjuntos invariantes "menores" juntamente com as órbitas que conectam estes subconjuntos. A metodologia adotada para a pesquisa se fundamentou na análise dedutiva, método que per- mitiu determinar o índice de Conley utilizando ferramentas de inclusões diferenciais, par-ín- dice e a teoria de Morse para se chegar a determinação do índice homológico.
13

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
14

Dynamical spectral sequences for Morse-Novikov and Morse-Bott complexes / Sequências espectrais dinâmicas para complexos de Morse-Novikov e Morse-Bott

Lima, Dahisy Valadão de Souza, 1986- 25 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 2018-08-25T10:15:50Z (GMT). No. of bitstreams: 1 Lima_DahisyValadaodeSouza_D.pdf: 22146296 bytes, checksum: c88725de657b032422b9e4614ccd91a9 (MD5) Previous issue date: 2014 / Resumo: O tema principal desta tese é o estudo de fluxos gradientes associados a campos vetoriais $-\nabla f$ em variedades fechadas, onde $f$ é uma função do tipo Morse, Morse circular e Morse-Bott. Para obter informações dinâmicas em cada caso, utilizamos ferramentas algébricas e topológicas, tais como sequências espectrais e matrizes de conexão. No contexto de Morse, consideramos um complexo de cadeias $(C,\Delta)$ gerado pelos pontos críticos de $f$ onde $\Delta$ conta (com sinal) o número de linhas do fluxo entre dois pontos críticos consecutivos. Uma análise via sequências espectrais $(E^{r},d^{r})$ é feita para se obter resultados de continuação global em superfícies. Nós relacionamos as diferenciais da $r$-ésima página de $(E^{r},d^{r})$ com cancelamentos dinâmicos entre pontos críticos. No caso de função de Morse circular $f:M \rightarrow S^{1}$, o método da varredura para um complexo de Novikov $(\mathcal{N},\Delta)$ associado $f$ e gerado pelos pontos críticos de $f$ é definido sobre o anel $\mathbb{Z}((t))$. Este método produz a cada etapa matrizes de Novikov. Provamos que a matriz final produzida pelo método da varredura tem entradas polinomiais, o que é surpreendente, já que as matrizes intermediárias podem ter séries infinitas como entradas. Apresentamos resultados que mostram que os módulos e diferenciais de uma sequência espectral associada a $(\mathcal{N},\Delta)$ podem ser recuperados através do método da varredura. Para fluxos gradientes associados a funções de Morse-Bott, as singularidades formam variedades críticas. Usamos a teoria do índice de Conley para obter uma caracterização do conjunto de matrizes de conexão para fluxos Morse-Bott. Obtemos resultados sobre o efeito no conjunto de matrizes de conexão causado por mudanças na ordem parcial e na decomposição de Morse de um conjunto invariante isolado / Abstract: The main theme in this thesis is the study of gradient flows associated to a vector field $-\nabla f$ on closed manifolds, where $f$ is either a Morse function, a circle-valued Morse function or a Morse-Bott function. In order to obtain dynamical information, we make use of algebraic and topological tools such as spectral sequences and connection matrices. In the Morse context, consider a chain complex $(C,\Delta)$ generated by the critical points of $f$, where $\Delta$ counts the number of flow lines between consecutive critical points with signs. A spectral sequence $(E^{r},d^{r})$ analysis is used to obtain results on global continuation of flows on surfaces. A link is established between the differentials on the $r$-th page of $(E^{r},d^{r})$ and cancellation of critical points. In the circle-valued Morse case $f:M \rightarrow S^{1}$, a sweeping algorithm for the Novikov chain complex $(\mathcal{N},\Delta)$ associated to $f$ and generated by the critical points of $f$ is defined over the ring $\mathbb{Z}((t))$. This algorithm produces at each stage Novikov matrices. We prove that the last Novikov matrix has polynomial entries which is quite surprising since the matrices in the intermediary stages may have infinite series entries. We also present results showing that the modules and differentials of the spectral sequence associated to $(\mathcal{N},\Delta)$ can be retrieved through the sweeping algorithm. For gradient flows associated to Morse-Bott functions, the singularities form critical manifolds. We use the Conley index theory for the critical manifolds in order to characterize the set of connection matrices for Morse-Bott flows. Results are obtained on the effects on the set of connection matrices caused by a change in the partial ordering and Morse decomposition of isolated invariant sets / Doutorado / Matematica / Doutora em Matemática
15

On the minimal number of periodic Reeb orbits on a contact manifold / Sur le nombre minimal d'orbites de reeb périodiques sur une variété de contact

Gutt, Jean 27 June 2014 (has links)
Le sujet de cette thèse est la question du nombre minimal d’orbites de Reeb distinctes sur une variété de contact qui est le bord d’une variété symplectique compacte. L’homologie symplectique S1-équivariante positive est un des outils principaux de cette thèse; elle est construite à partir d’orbites périodiques de champs de vecteurs hamiltoniens sur une variété symplectique dont le bord est la variété de contact considérée.Nous analysons la relation entre les différentes variantes d’homologie symplectique d’une variété symplectique exacte compacte (domaine de Liouville) et les orbites de Reeb de son bord. Nous démontrons certaines propriétés de ces homologies. Pour un domaine de Liouville plongé dans un autre, nous construisons un morphisme entre leurs homologies.Nous étudions ensuite l’invariance de ces homologies par rapport au choix de la forme de contact sur le bord. Nous utilisons l’homologie symplectique S1-équivariante positive pour donner une nouvelle preuve d’un théorème de Ekeland et Lasry sur le nombre minimal d’orbites de Reeb distinctes sur certaines hypersurfaces dans R2n. Nous indiquons comment étendre au cas de certaines hypersurfaces dans certains fibrés en droites complexes négatifs.Nous donnons une caractérisation et une nouvelle fa ç on de calculer l’indice de Conley-Zehnder généralisé, défini par Robbin et Salamon pour tout chemin de matrices symplectiques. Ceci nous a mené à développer de nouvelles formes normales de matrices symplectiques. / This thesis deals with the question of the minimal number of distinct periodic Reeb orbits on a contact manifold which is the boundary of a compact symplectic manifold.The positive S1-equivariant symplectic homology is one of the main tools considered in this thesis. It is built from periodic orbits of Hamiltonian vector fields in a symplectic manifold whose boundary is the given contact manifold.Our first result describes the relation between the symplectic homologies of an exact compact symplectic manifold with contact type boundary (also called Liouville domain), and the periodic Reeb orbits on the boundary. We then prove some properties of these homologies. For a Liouville domain embedded into another one, we construct a morphism between their homologies. We study the invariance of the homologies with respect to the choice of the contact form on the boundary.We use the positive S1-equivariant symplectic homology to give a new proof of a Theorem by Ekeland and Lasry about the minimal number of distinct periodic Reeb orbits on some hypersurfaces in R2n. We indicate how it extends to some hypersurfaces in some negative line bundles. We also give a characterisation and a new way to compute the generalized Conley-Zehnder index defined by Robbin and Salamon for any path of symplectic matrices. A tool for this is a new analysis of normal forms for symplectic matrices.
16

Transition matrix theory = Teoria da matriz de transição / Teoria da matriz de transição

Vieira, Ewerton Rocha, 1987- 03 May 2015 (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 2018-08-26T22:09:01Z (GMT). No. of bitstreams: 1 Vieira_EwertonRocha_D.pdf: 1632095 bytes, checksum: 5dc3208efc5649260ca62805c3e8e1b6 (MD5) Previous issue date: 2015 / Resumo: Nessa tese, apresentamos uma unificação da teoria das matrizes de transição algébrica, singular, topológica e direcional ao introduzir a matriz de transição (generalizada), a qual engloba todas as quatros citadas anteriormente. Alguns resultados de existência são apresentados bem como a verificação de que cada matriz de transição supracitada são casos particulares da matriz de transição (generalizada). Além disso, nós abordamos como as aplicações das quatros matrizes de transiçao, na teoria do índice de Conley, se traduzem para a matriz de transição (generalizada). Quando a matriz de transição (generalizada) satisfizer o requerimento adicional de cobrir o isomorfismo do índice de Conley F definido pelo fluxo, pode-se provar propriedades de existência e de conexão de órbitas. Essa matriz de transição com a propriedade de cobrir o isomorfismo F é definida como matriz de transição topológica generalizada e a utilizamos para obter conexões de órbitas num fluxo Morse-Smale sem órbitas periódicas bem como para obter conexões de órbitas numa continuação associada à sequência espectral dinâmica / Abstract: In this thesis, we present a unification of the theory of algebraic, singular, topological and directional transition matrices by introducing the (generalized) transition matrix which encompasses each of the previous four. Some transition matrix existence results are presented as well as the verification that each of the previous transition matrices are cases of the (generalized) transition matrix. Furthermore, we address how applications of the previous transition matrices to the Conley Index theory carry over to the (generalized) transition matrix. When this more general transition matrix satisfies the additional requirement that it covers flow-defined Conley-index isomorphisms, one proves algebraic and connection-existence properties. These general transition matrices with this covering property are referred to as generalized topological transition matrices and are used to consider connecting orbits of Morse-Smale flows without periodic orbits, as well as those in a continuation associated to a dynamical spectral sequence / Doutorado / Matematica / Doutor em Matemática
17

On the Weyl representation of metaplectic operators

Gosson, Maurice A. de January 2005 (has links)
We study the Weyl representation of metaplectic operators associated to a symplectic matrix having no non-trivial fixed point, and justify a formula suggested in earlier work of Mehlig and Wilkinson. We give precise calculations of the associated Maslov-type indices; these indices intervene in a crucial way in Gutzwiller’s formula of semiclassical mechanics, and are simply related to an index defined by Conley and Zehnder.
18

Conley-Morse Chain Maps

Moeller, Todd Keith 19 July 2005 (has links)
We introduce a new class of Conley-Morse chain maps for the purpose of comparing the qualitative structure of flows across multiple scales. Conley index theory generalizes classical Morse theory as a tool for studying the dynamics of flows. The qualitative structure of a flow, given a Morse decomposition, can be stored algebraically as a set of homology groups (Conley indices) and a boundary map between the indices (a connection matrix). We show that as long as the qualitative structures of two flows agree on some, perhaps coarse, level we can construct a chain map between the corresponding chain complexes that preserves the relations between the (coarsened) Morse sets. We present elementary examples to motivate applications to data analysis.
19

On the minimal number of periodic Reeb orbits on a contact manifold

Gutt, Jean 27 June 2014 (has links) (PDF)
Le sujet de cette thèse est la question du nombre minimal d'orbites de Reeb distinctes sur une variété de contact qui est le bord d'une variété symplectique compacte. L'homologie symplectique $S^1$-équivariante positive est un des outils principaux de cette thèse; elle est construite à partir d'orbites périodiques de champs de vecteurs hamiltoniens sur une variété symplectique dont le bord est la variété de contact considérée. Nous analysons la relation entre les différentes variantes d'homologie symplectique d'une variété symplectique exacte compacte (domaine de Liouville) et les orbites de Reeb de son bord. Nous démontrons certaines propriétés de ces homologies. Pour un domaine de Liouville plongé dans un autre, nous construisons un morphisme entre leurs homologies. Nous étudions ensuite l'invariance de ces homologies par rapport au choix de la forme de contact sur le bord. Nous utilisons l'homologie symplectique $S^1$-équivariante positive pour donner une nouvelle preuve d'un théorème de Ekeland et Lasry sur le nombre minimal d'orbites de Reeb distinctes sur certaines hypersurfaces dans $\R^{2n}$. Nous indiquons comment étendre au cas de certaines hypersurfaces dans certains fibrés en droites complexes négatifs. Nous donnons une caractérisation et une nouvelle façon de calculer l'indice de Conley-Zehnder généralisé, défini par Robbin et Salamon pour tout chemin de matrices symplectiques. Ceci nous a mené à développer de nouvelles formes normales de matrices symplectiques.
20

"Speak Your Mind and Speak it Clearly" : Discourse and the Importance of Voices in Boy Erased, Garrard Conley

Deneuville, Marie January 2019 (has links)
The voices of the autodiegetic narrator and its character counterpart in Boy Erased: A Memoir by Garrard Conley enter the debate around the ontology of voice in literary texts. Using this debate, I will provide an analysis of the voices in this memoir in order to prove the importance of assuming a voice for the narrator, to compensate for speech silenced through discourses and social contexts. The social contexts and discourses that surround the main character silence his speech, to the point that it can be actively used to control even the private self, as gay conversion therapy tries to do. This dangerous silence leads to a need to finally be heard, which is provided through the ontologically silent voice of the narrator. This evolvement of the character to the narrator is the reason why voice and the way it allows for heard speech is essential.

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