• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 16
  • 8
  • 7
  • 2
  • 1
  • 1
  • Tagged with
  • 38
  • 14
  • 11
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 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.
1

Problème de centre tangentiel et problème de monodromie pour certains Hamiltoniens non-génériques / Tangential center problem and monodromy problem for some non-generic Hamiltonians

Pontigo Herrera, Jessie Diana 05 February 2016 (has links)
Dans le cas générique Yu. S. Ilyashenko a donné une solution pour le problème tangentielle du centre et le probème de la monodromie. Néanmoins, on ne connaît pas la solution pour tous les cas non-génériques. Dans cette thèse on étudie une famille des équations hamiltoniennes non-génériques dont l'hamiltonien est un produit de polynômes réels irréductibles de dégre supérieur ou égal à 1. On étudie cette famille dans le but d'avoir un modèle d'équation hamiltonienne qui nous permette de comprendre d'autres cas non-génériques. Cette famille ne satisfait pas necessairement les conditions de généricité de transversalité à l'infini et n'a pas nécessairement tous les points singuliers aux niveaux distincts. Nous considerons quelques conditions géomètriques sur les hamiltoniens qu'on appelle bon partage du plan proyective réel et bonne multiplicité à l'infini. Ces conditions nous servent pour calculer l'orbite par monodromie des cycles évanescents. On résout le problème de la monodromie pour deux sous-familles dans cette famille d'hamiltoniennes. Une d'elles satisfait que tous les points critiques de type centre sont à des niveux critiques distincts, et l'autre satisfait que l'hamiltonien est invariant par la réflexion par rapport à l'axe des y. En utilisant la solution du problème de la monodromie on résout aussi le problème tangentiel du centre pour ces familles. / In the generic case Yu. S. Ilyashenko gave a solution of the tangential center problem and the monodromy problem. However, a solution for all non-generic cases is not known. In this thesis we study a family of non-generic Hamiltonians, whose Hamiltonian is a product of real polynomials of degree equal or bigger than 1. We study this family with the idea that a good understanding of this Hamiltonian model could help us to understand other non-generic cases later. In this family the genericity assumption of transversality at infinity fails and the coincidence of the critical values for different critical points is allowed. We consider some geometric conditions on the Hamiltonians of this family that we call good divide of the real projective plane and good multiplicity at infinity. These conditions help us to compute the orbit under monodromy of vanishing cycles. We give a solution of the monodromy problem of two sub-families in this family. One of them satisfying that all the center critical points are at different critical levels, and the other satisfying that the Hamiltonian is invariant under the reflection with respect to the y-axis. Using the solution of the monodromy problem we also provide a solution of the tangential center problem for those families.
2

On Affine Structures Which Come from Berkovich Geometry for K-trivial Finite Quotients of Abelian Varieties / アーベル多様体のK-自明な有限商のBerkovich幾何に付随するアファイン構造について

Goto, Keita 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24384号 / 理博第4883号 / 新制||理||1699(附属図書館) / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)准教授 尾髙 悠志, 教授 入谷 寛, 教授 森脇 淳 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
3

Spectral data for G-Higgs bundles

Schaposnik, Laura P. January 2013 (has links)
We develop a new geometric method of understanding principal G-Higgs bundles through their spectral data, for G a real form of a complex Lie group. In particular, we consider the case of G a split real form, as well as G = SL(2,R), U(p,p), SU(p,p), and Sp(2p,2p). Further, we give some applications of our results, and discuss open questions.
4

Broken Lefschetz fibrations on smooth four-manifolds

Williams, Jonathan Dunklin 12 October 2010 (has links)
It is known that an arbitrary smooth, oriented four-manifold admits the structure of what is called a broken Lefschetz fibration. Given a broken Lefschetz fibration, there are certain modifications, realized as homotopies of the fibration map, that enable one to construct infinitely many distinct fibrations of the same manifold. The aim of this paper is to prove that these modifications are sufficient to obtain every broken Lefschetz fibration in a given homotopy class of smooth maps. One notable application is that adding an additional projection move generates all broken Lefschetz fibrations, regardless of homotopy class. The paper ends with further applications and open problems. / text
5

Sobre a topologia das fibrações de Milnor / On the topology of the Milnor fibrations

Martins, Rafaella de Souza 16 February 2018 (has links)
Nesta tese abordaremos dois tipos de problemas relacionados aos célebres Teorema da Fibração de Milnor e Teorema da Fibração de Milnor-Lê para o caso real com valores críticos não isolados. Primeiramente, asseguramos fibrações do tipo Milnor-Lê para F : (Xm, 0) &rarr; (Yn, 0), germe de aplicação subanalítico com X e Y espaços subanalíticos sobre C \\ {0} uma curva subanalítica conexa em Y e sobre um subespaço analítico suave W &sub; Y de dimensão p, n &ge; p &ge; 2, sob algumas condições. Em particular, mostramos a existência das fibrações sobre o discriminantes de germe de aplicações subanalíticos, caso esse ainda não estudado na literatura, normalmente o conjunto dos valores críticos são desconsiderados. Finalizando nossa análise da categoria subanalítica, certificamos que existe a fibração de Milnor-Lê para f : (X, 0) &rarr;(Rp, 0), com dimensão de X maior que p &ge; 2, subanalítica e X subanalítico com valores críticos não isolados, definindo d-regularidade. Abordamos estes problemas utilizando resultados de campos de vetores rugosos. Em uma segunda etapa apresentamos um novo critério necessário e suficiente para verificar a importante propriedade de transversalidade de um germe de aplicação real f de classe Cl, l &ge; 1. Fazendo uso também de uma recente ferramenta desenvolvida, a D-regularidade, verificamos condições para a existência das fibrações do germe de aplicação &Psi; F, X : (Cn, 0) &rarr; (C, 0) não holomorfo, dado por &Psi; (z, z&#772;) = &Sigma;nj=1 kjtjzj a<sub<jzj bj, aj, bj &ge; 0 com aj = bj para pelo menos um j e aj &ne; bj para ao menos um j, com j = 1, ... , n. Observamos que &Psi;F, X são polinômios homogêneos pesados mistos com R+ -ação. Consideramos &Psi;F, X : (R2n ,0) &rarr; (R2, 0) germe de aplicação analítico real. Estudamos a topologia dessas fibrações nos reais, constatando que o discriminante tem dimensão 1 e por isso tem ambas as fibrações conhecidas. Por fim exibimos um homeomorfismo entre as fibras dos valores regulares e dos valores críticos. / In this thesis two types of problems related to the famous Milnor Fibration Theorem and Milnor-Lê Fibration Theorem for the real case with non-isolated critical values will be addressed. Primarily, we assure the fibrations of type Milnor-Lê for the germ F : (X, 0) &rarr; (Y, 0) subanalytic with X and Y subanalytic spaces on C \\ {0} a subanalytic connected curve in Y and over a smooth analytical subspace W &sub; Y of dimension p, n &ge p &ge; 2, under some conditions. In particular, we show the existence of the fibrations about the discriminants of subanalytical map-germ, if this not been studied in the literature, usually the set of critical values are disregarded. Finalizing our analysis of this subanalytic category, we certify that there exist the fibrations of type Milnor-Lê to f : (X, 0) &rarr; (Rp, 0), with dimension of X greater than p &ge; 2, subanalytic and X subanalytic with non-isolated critical values, setting d -regularity. We address these problems using results of the rugose vector fields. In a second part, we present a new necessary and sufficient criterion to verify the important transversality property of a real map-germ f of class Cl, l &ge; 1. Using a recent developed tool, D-regularity, we verify conditions for the existence of the fibrations of map-germ &Psi; F, X : (Cn, 0) &rarr; (C, 0) non holomorphic, given by &Psi; (z, z&#772;) = &Sigma;nj=1 kjtjzj ajzb<sup<j, aj, bj &ge; 0 with aj = bj for at least one j and aj &ne; bj for at leeast one j = 1, ..., n. We note that &Psi; F, X are mixed weighted homogeneous polynomials with R+-action. We consider &Psi;F, X : (R2n, 0) &rarr; (R2, 0) real analytic map-germ. We studied the topology of these fibrations, noting that the discriminant has dimension 1 and therefore has both the fibrations known. Lastly we show a homeomorphism between the fibers of the regular values and the critical values for a case special this family.
6

Sobre a topologia das fibrações de Milnor / On the topology of the Milnor fibrations

Rafaella de Souza Martins 16 February 2018 (has links)
Nesta tese abordaremos dois tipos de problemas relacionados aos célebres Teorema da Fibração de Milnor e Teorema da Fibração de Milnor-Lê para o caso real com valores críticos não isolados. Primeiramente, asseguramos fibrações do tipo Milnor-Lê para F : (Xm, 0) &rarr; (Yn, 0), germe de aplicação subanalítico com X e Y espaços subanalíticos sobre C \\ {0} uma curva subanalítica conexa em Y e sobre um subespaço analítico suave W &sub; Y de dimensão p, n &ge; p &ge; 2, sob algumas condições. Em particular, mostramos a existência das fibrações sobre o discriminantes de germe de aplicações subanalíticos, caso esse ainda não estudado na literatura, normalmente o conjunto dos valores críticos são desconsiderados. Finalizando nossa análise da categoria subanalítica, certificamos que existe a fibração de Milnor-Lê para f : (X, 0) &rarr;(Rp, 0), com dimensão de X maior que p &ge; 2, subanalítica e X subanalítico com valores críticos não isolados, definindo d-regularidade. Abordamos estes problemas utilizando resultados de campos de vetores rugosos. Em uma segunda etapa apresentamos um novo critério necessário e suficiente para verificar a importante propriedade de transversalidade de um germe de aplicação real f de classe Cl, l &ge; 1. Fazendo uso também de uma recente ferramenta desenvolvida, a D-regularidade, verificamos condições para a existência das fibrações do germe de aplicação &Psi; F, X : (Cn, 0) &rarr; (C, 0) não holomorfo, dado por &Psi; (z, z&#772;) = &Sigma;nj=1 kjtjzj a<sub<jzj bj, aj, bj &ge; 0 com aj = bj para pelo menos um j e aj &ne; bj para ao menos um j, com j = 1, ... , n. Observamos que &Psi;F, X são polinômios homogêneos pesados mistos com R+ -ação. Consideramos &Psi;F, X : (R2n ,0) &rarr; (R2, 0) germe de aplicação analítico real. Estudamos a topologia dessas fibrações nos reais, constatando que o discriminante tem dimensão 1 e por isso tem ambas as fibrações conhecidas. Por fim exibimos um homeomorfismo entre as fibras dos valores regulares e dos valores críticos. / In this thesis two types of problems related to the famous Milnor Fibration Theorem and Milnor-Lê Fibration Theorem for the real case with non-isolated critical values will be addressed. Primarily, we assure the fibrations of type Milnor-Lê for the germ F : (X, 0) &rarr; (Y, 0) subanalytic with X and Y subanalytic spaces on C \\ {0} a subanalytic connected curve in Y and over a smooth analytical subspace W &sub; Y of dimension p, n &ge p &ge; 2, under some conditions. In particular, we show the existence of the fibrations about the discriminants of subanalytical map-germ, if this not been studied in the literature, usually the set of critical values are disregarded. Finalizing our analysis of this subanalytic category, we certify that there exist the fibrations of type Milnor-Lê to f : (X, 0) &rarr; (Rp, 0), with dimension of X greater than p &ge; 2, subanalytic and X subanalytic with non-isolated critical values, setting d -regularity. We address these problems using results of the rugose vector fields. In a second part, we present a new necessary and sufficient criterion to verify the important transversality property of a real map-germ f of class Cl, l &ge; 1. Using a recent developed tool, D-regularity, we verify conditions for the existence of the fibrations of map-germ &Psi; F, X : (Cn, 0) &rarr; (C, 0) non holomorphic, given by &Psi; (z, z&#772;) = &Sigma;nj=1 kjtjzj ajzb<sup<j, aj, bj &ge; 0 with aj = bj for at least one j and aj &ne; bj for at leeast one j = 1, ..., n. We note that &Psi; F, X are mixed weighted homogeneous polynomials with R+-action. We consider &Psi;F, X : (R2n, 0) &rarr; (R2, 0) real analytic map-germ. We studied the topology of these fibrations, noting that the discriminant has dimension 1 and therefore has both the fibrations known. Lastly we show a homeomorphism between the fibers of the regular values and the critical values for a case special this family.
7

Μια εισαγωγή στη νηματοποίηση του Hopf

Μπάρτζος, Ευάγγελος 11 October 2013 (has links)
Στη διπλωματική αυτή εργασία μελετάται η πιο απλή περίπτωση από τις νηματοποιήσεις του Hopf και παράλληλα η γεωμετρική δομή της τρισδιάστατης σφαίρας. Για το σκοπό αυτό εισάγονται οι έννοιες των κβατερνίων και βασικά στοιχεία από τη θεωρία πολλαπλοτήτων. / An introduction of the simplest Hopf fibration and an elementary study of the 3-sphere are the basic aims of this graduation thesis. Besides, quaternions and elements of manifold theory are widely used.
8

Signature modulo 8 of fibre bundles

Rovi, Carmen January 2015 (has links)
Topology studies the geometric properties of spaces that are preserved by continuous deformations. Manifolds are the main examples of topological spaces, with the local properties of Euclidean space in an arbitrary dimension n. They are the higher dimensional analogs of curves and surfaces. For example a circle is a one-dimensional manifold. Balloons and doughnuts are examples of two-dimensional manifolds. A balloon cannot be deformed continuously into a doughnut, so we see that there are essential topological differences between them. An "invariant" of a topological space is a number or an algebraic structure such that topologically equivalent spaces have the same invariant. For example the essential topological difference between the balloon and the doughnut is calculated by the "Euler characteristic", which is 2 for a balloon and 0 for a doughnut. In this thesis I investigate the relation between three different but related invariants of manifolds with dimension divisible by 4: the signature, the Brown-Kervaire invariant and the Arf invariant. The signature invariant takes values in the set (...;-3;-2;-1; 0; 1; 2; 3; ...) of integers. In this thesis we focus on the signature invariant modulo 8, that is its remainder after division by 8. The Brown-Kervaire invariant takes values in the set (0; 1; 2; 3; 4; 5; 6; 7). The Arf invariant takes values in the set (0; 1). The main result of the thesis uses the Brown-Kervaire invariant to prove that for a manifold with signature divisible by 4, the divisibility by 8 is decided by the Arf invariant. The thesis is entirely concerned with pure mathematics. However it is possible that it may have applications in mathematical physics, where the signature modulo 8 plays a significant role.
9

Singular Milnor Fibrations / Fibrações de Milnor singulares

Ribeiro, Maico Felipe Silva 28 February 2018 (has links)
In this work we present the most recent developments in the direction of local fibrations structures of analytic singularities. Using techniques and tools from stratification theory we prove structural theorems in the stratified sense, which will be called singular Milnor tube fibration and Milnor-Hamm sphere fibration. In addition, we present algorithms with the purpose of creating a large number of examples in this new setting and compare our results obtained with the current ones found in the literature. Our results generalize all previous result in both cases: in the classical and in the stratified ones. / Neste trabalho apresentamos os mais recentes desenvolvimentos na direção de estruturas de fibrações locais de singularidades analíticas. Usando técnicas e ferramentas da teoria de estratificação, provamos alguns teoremas estruturais no sentido estratificado, os quais serão chamados fibração singular de Milnor sobre o tubo e fibração de Milnor-Hamm sobre a esfera. Além disso, apresentamos algoritmos com o intuito de criar uma ampla variedade de exemplos e comparamos nossos resultados com os atuais encontrados na literatura. Nossos resultados generalizam todos os previamente existentes tanto no caso clássico, quanto no sentido estratificado.
10

Some problems in algebraic topology : on Lusternik-Schnirelmann categories and cocategories

Gilbert, William J. January 1967 (has links)
In his thesis we are concerned with certain numerical invariants of homotopy type akin to the Lusternik-Schnirelmann category and cocategory. In a series of papers I. Bernstein, T. Ganea, and P.J. Hilton developed the concepts of the category and weak category of a topological space. They also considered the related concepts of conilpotency and cup product length of a space and the weak category of a map. Later T. Ganea gave another definition of category and weak category (which we shall write as G-cat and G-wcat) in terms of vibrations and cofibrations and hence this dualizes easily in the sense of Eckmann-Hilton. We find the relationships between these invariants and then find various examples of spaces which show that the invariants are all different except cat and G-cat. The results are contained in the following theorem. The map $e:B -> OmegaSigma B$ is the natural embedding. All the invariants are normalized so as to take the value 0 on contractible spaces. THEOREM Let B have the homotopy type of a simply connected CW-complex, then $cat B = G-cat B geq G-wcat B geq wcat B geq wcat e geq conil B geq cup-long B$ and furthermore all the inequalities can occur. All the examples are spaces of the form $B = S^qcup_alpha e^n$ where $alphain pi_{n-1} (S^q)$. When B is of this form, we obtain conditions for the category and the weak categories of B to be less than or equal to one of the terms of Hopf invariants of $alpha$. We use these conditions to prove the examples. We then prove the dual theorem concerning the relationships between the invariants cocategory, weak cocategory, nilpotency and Whitehead product length. THEOREM Let A be countable CW-complex, then $cocat A geq wcocat A geq nil A geq W-long A$ and furthermore all the inequalities can occur. The proof is not dual to the first theorem, though the examples we use to show that the inequalities can exist are all spaces with two non-zero homotopy groups. The most interesting of these examples is the space A with 2 non-zero homotopy groups, $mathbb Z$ in dimension 2 and ${mathbb Z}_4$ in dimension 7 with k-invariant $u^4 in H^8(mathbb Z, 2; {mathbb Z}_4)$. This space is not an H-space, but has weak cocategory 1. The condition $wcocat A leq 1$ is equivalent to the fact that d is homotopic to 0 in the fibration $D -d-> A -e-> OmegaSigma A$. In order to show that wcocat A = 1 we have to calculate to cohomology ring of $OmegaSigma K(mathbb Z,2)$. The method we use to do this is the same as that used to calculate the cohomology ring of $OmegaSigma S^{n+1}$ using James' reduced product construction. Finally we show that for the above space A the fibration $Omega A -g-> A^S -f-> A$ has a retraction $ ho$ such that $ hocirc g$ is homotopic to 1 even though A is not an H-space.

Page generated in 0.1334 seconds