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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.
1

Cohomologia de feixes em estruturas O-minimais / Sheaf cohomology in O-minimal structures

Jonas Renan Moreira Gomes 15 June 2018 (has links)
Este trabalho estuda a demonstração de existência de uma teoria de cohomologia em estruturas o-minimais arbitrárias, conforme o trabalho de Edmundo, Jones e Peatfield. / This work studies the proof of the existence of sheaf cohomology theory in arbitrary o-minimal structures, following the work of Edmundo, Jones and Peatfield.
2

Cohomologia de feixes em estruturas O-minimais / Sheaf cohomology in O-minimal structures

Gomes, Jonas Renan Moreira 15 June 2018 (has links)
Este trabalho estuda a demonstração de existência de uma teoria de cohomologia em estruturas o-minimais arbitrárias, conforme o trabalho de Edmundo, Jones e Peatfield. / This work studies the proof of the existence of sheaf cohomology theory in arbitrary o-minimal structures, following the work of Edmundo, Jones and Peatfield.
3

Bounding Betti numbers of sets definable in o-minimal structures over the reals

Clutha, Mahana January 2011 (has links)
A bound for Betti numbers of sets definable in o-minimal structures is presented. An axiomatic complexity measure is defined, allowing various concrete complexity measures for definable functions to be covered. This includes common concrete measures such as the degree of polynomials, and complexity of Pfaffian functions. A generalisation of the Thom-Milnor Bound [17, 19] for sets defined by the conjunction of equations and non-strict inequalities is presented, in the new context of sets definable in o-minimal structures using the axiomatic complexity measure. Next bounds are produced for sets defined by Boolean combinations of equations and inequalities, through firstly considering sets defined by sign conditions, then using this to produce results for closed sets, and then making use of a construction to approximate any set defined by a Boolean combination of equations and inequalities by a closed set. Lastly, existing results [12] for sets defined using quantifiers on an open or closed set are generalised, using a construction from Gabrielov and Vorobjov [11] to approximate any set by a compact set. This results in a method to find a general bound for any set definable in an o-minimal structure in terms of the axiomatic complexity measure. As a consequence for the first time an upper bound for sub-Pfaffian sets defined by arbitrary formulae with quantifiers is given. This bound is singly exponential if the number of quantifier alternations is fixed.
4

O-minimal De Rham cohomology / Cohomologia de De Rham o-minimal

Figueiredo, Rodrigo 15 December 2017 (has links)
The aim of this dissertation lies in establishing an o-minimal de Rham cohomology theory for smooth abstract-definable manifolds in an o-minimal expansion of the real field which admits smooth cell decomposition and defines the exponential function, by following the classical de Rham cohomology. We can specify the o-minimal cohomology groups and attain some properties as the existence of Mayer-Vietoris sequence and the invariance under smooth abstract-definable diffeomorphisms. However, in order to obtain the invariance of our o-minimal cohomology under abstract-definable homotopy we must, working in a tame context that defines sufficiently many primitives, assume the validity of a statement related to Bröcker\'s problem. / O objetivo desta tese reside em estabelecer uma cohomologia de De Rham o-minimal para variedades definíveis abstratas lisas em uma expansão o-minimal do corpo ordenado dos reais, a qual admite decomposição celular lisa e define a função exponencial, seguindo a cohomologia de De Rham clássica. Além de especificarmos os grupos da cohomologia de Rham o-minimal, obtemos algumas propriedades, como a existência da sequência de Mayer-Vietoris e a invariância sob difeomorfismos definíveis abstratos lisos. Todavia, a fim de lograrmos a invariância de nossa cohomologia o-minimal sob homotopia definível abstrata devemos, além de trabalhar num contexto moderado no qual muitas primitivas são definidas, assumir a validade de uma asserção relacionada ao problema de Bröcker.
5

Elimination des quantificateurs dans le cadre quasi-analytique / Quantifier elimination in the quasi-analytic framework

Michas, Francois 21 June 2012 (has links)
Nous associons à tout polydisque compact B [appartenant à] Rn une algèbre CB de fonctions réelles de classe C∞ définies au voisinage de B. La collection des algèbres CB est supposée stable par certaines opérations, dont la composition et la dérivation partielle. Nous supposons de plus que, lorsque B est centrée à l’origine, l’algèbre des germes à l’origine des éléments de CB est quasianalytique (c’est à dire qu’elle ne contient pas de germe plat). A l’aide de ces fonctions, nous définissons des ensembles C-semi- analytiques et C-sous-analytiques comme on le fait traditionnellement en géométrie analytique réelle. Notre résultat principal est un théorème du type Tarski-Seidenberg pour ces ensembles. Son énoncé dit essentiellement que les ensembles sous-C-analytiques peuvent être définis par des égalités et des inégalités satisfaites par des termes obtenus en composant des fonctionsdes algèbres C_B , les fonctions x → x1/n , et la fonction x → 1/x. Sa preuve se fait en exprimant les solutions de sytèmes d’équations quasianalytiques au moyen d’un théorème de préparation issu de la théorie des modèles / We associate to every compact polydisk B [belonging to ] Rn an algebra CB of real functions defined in a neighborhood of B. The collection of these algebras is supposed to be closed under several operations, such as composition and partial derivatives. Moreover, if the center of B is the origin, we assume that the algebra of germs at the origin of elements of CB is quasianalytic (it does not contain any flat germ). We define with these functions the collection of C-semianalytic and C-subanalytic sets according to the classical process in real analytic geometry. Our main result is an analogue of Tarski-Seidenberg's usual result for these sets. It says that the sub-C-subanalytic sets may be described by means of equalities and inequalities by terms obtained by composition of elements of the algebras CB, the functions x->^{1/n} and the function x->1/x. It is proved via a model theoretic preparation theorem
6

Structure métrique et géométrie des ensembles définissables dans des structures o-minimales / Metric and geometric structures of definable sets in o-minimal structures

Nguyen, Xuan Viet Nhan 01 October 2015 (has links)
L'objectif de la thèse est l'étude des propriétés géométriques des ensembles définissables dans les structures o-minimales et de ses applications. Il existe trois principaux résultats présentés dans cette thèse. Le premier est une preuve géométrique de l'existence de stratifications vérifiant les conditions (a) et (b) de Whitney d'ensembles définissables. Ce résultat fut d'abord prouvé par T. L. Loi en 1994 par une autre méthode. Le second est une preuve de l'existence de stratifications de Lipschitz (dans le sens de Mostowski) pour les ensembles définissables dans une structure o-minimale polynomialement bornée. Ceci est une généralisation de résultats de Parusin'ski en 1994 pour les ensembles sous-analytiques. Le troisième résultat est au sujet de la continuité des variations de géométrie intégrale appelées courbures de Lipschitz Killing locales, qui ont été introduites par A. Bernig et L. Broker en 2002. Nous prouvons que les courbures de Lipschitz Killing locales sont continues le long de strates de stratifications de Whitney d'ensembles définissable dans une structure o-minimale polynomialement bornée, et si les stratifications sont (w) régulières alors les courbures de Lipschitz Killing locales sont localement lipschitziennes le long des strates. / The thesis focus on study geometric properties of definable sets in o-minimal structures and its applications. There are three main results presented in this thesis. The first is a geometric proof of the existence of Whitney (a) and (b)-regular stratifications of definable sets. The result was initially proved by T. L. Loi in 1994 by using another method. The second is a proof of existence of Lipschitz stratifications (in the sense of Mostowski) of definable sets in a polynomially bounded o-minimal structure. This is a generalization of Parusinski's 1994 result for subanalytic sets. The third result is about the continuity of of variations of integral geometry called local Lipschitz Killing curvatures which were introduced by A. Bernig and L. Broker in 2002. We prove that Lipschitz Killing curvatures are continuous along strata of Whiney stratifications of definable sets in a polynomially bounded o-minimal structure. Moreover, if the stratifications are (w)-regular the Lipspchitz Killing curvatures are locally Lipschitz.

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