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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.
271

Uma versão parametrizada do teorema de Borsuk-Ulam / A parametrized version of the Borsuk-Ulam theorem

Nelson Antonio Silva 18 March 2011 (has links)
O teorema clássico de Borsuk-Ulam nos dá informações à respeito de aplicações \'S POT. n\' \'SETA\' \'R POT. n\', no qual \'S POT. n\' é um \'Z IND. 2\' -espaço livre. O teorema afirma que existe pelo menos uma órbita que é enviada em um único ponto em \'R POT. n\'. Dold [9] estendeu este problema para o contexto de fibrados, considerando aplicações f : S (E) \'SETA\' \'E POT. \'prime\'\' nos quais preservam fibras; aqui, S (E) denota o espaço total do fibrado em esfera sobre B associado ao fibrado vetorial E \'SETA\' B e \'E POT. \'prime\'\' \'SETA\' B é o outro fibrado vetorial. O objetivo desse trabalho é provar esta versão do teorema de Borsuk-Ulam obtida por Dold, chamada versão parametrizada do teorema de Borsuk-Ulam. Nós também provamos uma versão cohomológica deste problema / The classical Borsuk-Ulam Theorem gives information about maps \'S POT. n\' \'ARROW\' \'R POT. n\' where \'S POT. n\' has a free action of the cyclic group \'Z IND. 2\'. The theorem states that there is at least one orbit which is sent to a single point in \'R POT. n\'. Dold [9] extended this problem to a fibre-wise setting, by considering maps f : S (E) \'ARROW\' \' E POT. prime\' which preserve fibres; here, S (E) denotes the total space of the sphere bundle associated over B to a vector bundle E \'ARROW\' B and \'E POT. prime\' \'ARROW\' B is other vector bundle over B. The purpose of this work is to prove this version of the Borsuk-Ulam theorem obtained by A. Dold, called parametrized version of the Borsuk-Ulam theorem. We also prove a cohomological generalization of this problem
272

Grau de aplicações G-equivariantes entre variedades generalizadas / Degree of G-equivariant maps between generalized manifolds

Norbil Leodan Cordova Neyra 09 June 2014 (has links)
Neste trabalho estenderemos os resultados obtidos por Hara [34] e J. Jaworowski [38] substituindo as G-variedades por G-variedades generalizadas sobre Z. Além disso, provamos uma fórmula de comparação geral para grau de aplicações de uma variedade generalizada sobre uma esfera que são equivariantes com respeito a ações de grupos finitos, obtendo uma generalização do resultado de A. Kushkuley e Z. Balanov [40] / In this work, we extend the results obtained by Y. Hara [34] and J. Jaworowski [38] by replacing the free G-manifolds by free generalized G-manifolds over Z. Moreover, we prove a general comparison formula for degrees of equivariant maps from a generalized manifold to a sphere which are equivariant with respect to finite group actions, obtaining a generalization of the result of A. Kushkuley and Z. Balanov [40]
273

O produto cartesiano de duas esferas mergulhado em uma esfera em codimensão um / Product of two spheres embedded in sphere in codimension one

Northon Canevari Leme Penteado 22 February 2011 (has links)
James W. Alexander, no artigo[1],mostra que se tivermos um mergulho PL f : \'S POT. 1\' × \'S POT. 1\' \'S POT. 3\', então o fecho de uma das componentes conexas de \'S POT. 3\' f(\'S POT. 1\' × \'S POT. 1\') é homeomorfo a um toro sólido, isto é, homeomorfo a \'S POT. 1\' × \'D POT. 2\'. Este teorema ficou conhecido por Teorema do toro de Alexander. Nesta dissertação, estamos detalhando a demonstração deste teorema feita em[25] que é diferente da demonstração apresentada em [1]. Mais geralmente, para um mergulho diferenciável f : \'S POT. p\' × \'S POT. q\' \'S POT. p + q+1\' , demonstra-se que o fecho de uma das componentes conexasde \'S POT. p +q + 1\' f(\'S POT. p\' × \'S POT. q\') é difeomorfo a \'S POT. p\' × \'D POT. q + 1\' se p q 1 e p + q \'DIFERENTE DE\' 3 ou se p = 2 e q = 1 um dos fechos será homeomorfo a \'S POT. 2\' × \'D POT. 2\' , nesta dissertação estaremos também detalhando estas demonstrações feita em [20] / James W. Alexander shows in[1] that the closure of one of the two connected components of \'S POT. 3\'f( \'S POT. 1 × \'S POT. 1\') is homeomorphic to a solid torus \'S POT. 1\' × \'D POT. 2\' , where f : \'S POT. 1\' ×\' SPOT. 1\' \'S POT. 3\' is a PL embedding. This result became known as Alexanders torus theorem. In this dissertation we are detailing the proof of this theorem made in[25] which is different from the demonstration presented in[1]. More generally, when considering a smooth embeding f : \'S POT. p\' × \'S POT. q\' \' SPOT. p+q+1\' , it is demonstrated that the closure of one of the two connected components \'S POT. p+q+1\' f (\'S POT. p\' × \'S POT. q\' ) is diffeomorphic to \'S POT. p\' × \'D POT. q+1\' if p q 1 and p+q \'DIFFERENT OF\' 3 or if p = 2 and q = 1 one of the closures will be homeomorphic to \'S POT. 2\' × \'D POT. 2\'. In this work we are also detailing the proves made in[20]
274

Teorida de G-índice e grau de aplicações G-equivariantes / G-index theory and degree of G-equivariant maps

Norbil Leodan Cordova Neyra 07 May 2010 (has links)
Antes da publicação do trabalho An ideal-valued cohomological index theory with applications to Borsuk-Ulam and Bourgin-Yang theorems\"de Fadell e Husseini [20], haviam sido apenas considerados índices numéricos de G-espaços, nos casos G =\'Z IND. 2\' e G um grupo finito. No entanto, tais índices numéricos são obviamente insuficientes no caso de grupos mais complexos, como por exemplo a 1-esfera \'S POT. 1\'. Neste contexto, Fadell e Husseini introduziram o chamado Indice cohomológico de valor ideal: a cada G-espaço X paracompacto, eles associaram um ideal \'Ind POT. G\' (X;K) do anel de cohomología H*(BG;K), onde a cohomologia de Cech H* é considerada com coeficientes em um corpo K e BG é o espaço classificante do grupo G. Além disso, Fadell e Husseini associaram a este ideal o Índice cohomológico de valor numérico, o qual é definido como sendo a dimensão do K-espaço vetorial obtido do quociente entre o anel H*(BG;K) e o ideal \'Ind POT. G\' (X;K). O objetivo principal deste trabalho é apresentar um estudo detalhado deste índice e utilizá-lo no estudo dos resultados sobre grau de aplicações G-equivariantes provados por Hara em \"The degree of equivariant maps\"[24] / Before the appearance of the paper An ideal-valued cohomological index theory with applications to Borsuk-Ulam and Bourgin-Yang theorems\"of Fadell and Husseini [20], had been considered numerical indices of G-spaces, when G = \'Z IND. 2\' and when G is a finite group. However, such numerical indices are obviously insufficient in the case of groups more complexes, for example, G =\'S POT 1\'. In this context Fadell andHusseini, introduced the called valued-ideal cohomological index: to every paracompact G-space X they associated an ideal \'Ind POT. G\' (X,K) of the cohomology ring H*(BG;K), where the Cech cohomology H* is considered with coefficients in a field K and BG is the classifying space of the group G. Moreover, they associated to this ideal the numerical valued cohomological index, that is, the dimension of K-vector space obtained by the quotient between the ring H*(BG;K) and the ideal \'Ind POT. G\' (X,K). The main objective of this work is to present a detailed study of this index and use such index on the study of results on degree of equivariant maps proved by Hara in his paper The degree of equivariant maps\"[24]
275

Teoremas de decomposição, degenerescência e anulamento em característica positiva / Decomposition, degeneration and vanishing theorems in positive characteristic

Cardoso, Nuno Filipe de Andrade, 1988- 25 August 2018 (has links)
Orientador: Marcos Benevenuto Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-25T16:48:31Z (GMT). No. of bitstreams: 1 Cardoso_NunoFilipedeAndrade_M.pdf: 1858794 bytes, checksum: bbe47182338feb3de60b480df87b52a7 (MD5) Previous issue date: 2014 / Resumo: Os teoremas de degenerescência de Hodge e de anulamento de Kodaira, Akizuki e Nakano são de suma importância na teoria de variedades complexas. Usando o teorema de comparação de Serre, ambos podem ser traduzidos para o contexto de esquemas projetivos e suaves sobre um corpo de característica zero. Para corpos de característica positiva, no entanto, os dois deixam de valer sem hipóteses adicionais, sendo que os primeiros contra-exemplos foram encontrados por Mumford e Raynaud. O objetivo desta dissertação é apresentar um teorema devido a Deligne e Illusie que assegura a degenerescência da seqüência espectral de Hodge-de Rham e uma versão do teorema de Kodaira, Akizuki e Nakano para certos esquemas projetivos e suaves sobre um corpo perfeito de característica positiva. Nos propusemos a dar um tratamento, na medida do possível, auto-suficiente / Abstract: The Hodge degeneration theorem and the Kodaira, Akizuki and Nakano's vanishing theorem are of paramount importance in the theory of complex manifolds. Using Serre's comparison theorem, both can be translated to the context of smooth projective schemes over a field of characteristic zero. For fields of positive characteristic, however, both fail to hold without additional hypothesis, and the first counterexamples were found by Mumford and Raynaud. Our goal in this dissertation is to present a theorem due to Deligne and Illusie that ensures the degeneration of the Hodge-de Rham spectral sequence and a version of the theorem of Kodaira, Akizuki and Nakano for certain smooth projective schemes over a perfect field of positive characteristic. We tried to keep the treatment as self-contained as possible / Mestrado / Matematica / Mestre em Matemática
276

Une résolution projective pour le second groupe de Morava pour p>=5 et applications / A projective resolution of the second Morava group for p >3 and applications

Lader, Olivier 31 October 2013 (has links)
Dans les années 80, Shimomura a déterminé les groupes d'homotopie du spectre de Moore V(0) localisé par rapport à K(2) la deuxième K-théorie de Morava. Plus tard, avec les travaux de Devinatz et Hopkins est apparu une autre suite spectrale convergeant vers les précédents groupes d'homotopies. Lorsque le paramètre premier p de la théorie K(2) est supérieur ou égal à cinq, la précédente suite spectrale dégénère. Ainsi, déterminer ces groupes d'homotopie revient à calculer les groupes de cohomologie du groupe stabilisateur de Morava à coefficients dans l'anneau de Lubin-Tate modulo p. En 2007, Henn a démontré l'existence, lorsque p > 3, d'une résolution projective du groupe de Morava de longueur quatre. Dans cette thèse, nous précisons une telle résolution projective. On l'applique ensuite au calcul effectif des groupes de cohomologie à coefficients dans l'anneau de Lubin-Tate modulo p. Enfin, on donne une seconde application, en redémontrant un résultat de Hopkins non publié sur le groupe de Picard de la catégorie des spectres K(2)-locaux. / In the 80's, Shimomura has computed the homotopy groups of the Moore spectrum V(0) localized with respect to Morava K-theory K(2). Some years later, Devinatz and Hopkins found an other spectral sequence converging to those homotopy groups. When the prime paramater p of K(2) is greather or equal to five, the preceding spectral collapses. Thus, computing those homotopy groups consists in computing the cohomology groups of Morava Stabilizer Group with coefficients in the Lubin-Tate ring mod p. In 2007, Henn has showed that there exists, when p >3, a projective resolution of the Morava stabilizer group of length four. In this thesis, we give a more precise description of this resolution. Then, we use it for the computation of the cohomology groups of Morava Stabilizer Group with coefficients in the Lubin-Tate ring mod p. As a second application, we give an other proof of the unpublished result of Hopkins on the Picard group of the K(2)-local spectrum category.
277

Sur les groupes d’homotopie des sphères en théorie des types homotopiques / On the homotopy groups of spheres in homotopy type theory

Brunerie, Guillaume 15 June 2016 (has links)
L’objectif de cette thèse est de démontrer que π4(S3) ≃ Z/2Z en théorie des types homotopiques. En particulier, c’est une démonstration constructive et purement homotopique. On commence par rappeler les concepts de base de la théorie des types homotopiques et on démontre quelques résultats bien connus sur les groupes d’homotopie des sphères : le calcul des groupes d’homotopie du cercle, le fait que ceux de la forme πk(Sn) avec k < n sont triviaux et la construction de la fibration de Hopf. On passe ensuite à des outils plus avancés. En particulier, on définit la construction de James, ce qui nous permetde démontrer le théorème de suspension de Freudenthal et le fait qu’il existe un entier naturel n tel que π4(S3) ≃ Z/2Z. On étudie ensuite le produit smash des sphères, on construit l’anneau de cohomologie des espaces et on introduit l’invariant de Hopf, ce qui nous permet de montrer que n est égal soit à 1, soit à 2. L’invariant de Hopf nous permet également de montrer que tous les groupes de la forme π4n−1(S2n) sont infinis. Finalement, on construit la suite exacte de Gysin, ce qui nous permet de calculer la cohomologie de CP2 et de démontrer que π4(S3) ≃ Z/2Z, et que plus généralement on a πn+1(Sn) ≃ Z/2Z pour tout n ≥ 3 / The goal of this thesis is to prove that π4(S3) ≃ Z/2Z in homotopy type theory. In particular it is a constructive and purely homotopy-theoretic proof. We first recall the basic concepts of homotopy type theory, and we prove some well-known results about the homotopy groups of spheres: the computation of the homotopy groups of the circle, the triviality of those of the form πk(Sn) with k < n, and the construction of the Hopf fibration. We then move to more advanced tools. In particular, we define the James construction which allows us to prove the Freudenthal suspension theorem and the fact that there exists a natural number n such that π4(S3) ≃ Z/nZ. Then we study the smash product of spheres, we construct the cohomology ring of a space, and we introduce the Hopf invariant, allowing us to narrow down the n to either 1 or 2. The Hopf invariant also allows us to prove that all the groups of the form π4n−1(S2n) are infinite. Finally we construct the Gysin exact sequence, allowing us to compute the cohomology of CP2 and to prove that π4(S3) ≃ Z/2Z and that more generally πn+1(Sn) ≃ Z/2Z for every n ≥ 3
278

Goldman Bracket : Center, Geometric Intersection Number & Length Equivalent Curves

Kabiraj, Arpan January 2016 (has links) (PDF)
Goldman [Gol86] introduced a Lie algebra structure on the free vector space generated by the free homotopy classes of oriented closed curves in any orientable surface F . This Lie bracket is known as the Goldman bracket and the Lie algebra is known as the Goldman Lie algebra. In this dissertation, we compute the center of the Goldman Lie algebra for any hyperbolic surface of finite type. We use hyperbolic geometry and geometric group theory to prove our theorems. We show that for any hyperbolic surface of finite type, the center of the Goldman Lie algebra is generated by closed curves which are either homotopically trivial or homotopic to boundary components or punctures. We use these results to identify the quotient of the Goldman Lie algebra of a non-closed surface by its center as a sub-algebra of the first Hochschild cohomology of the fundamental group. Using hyperbolic geometry, we prove a special case of a theorem of Chas [Cha10], namely, the geometric intersection number between two simple closed geodesics is the same as the number of terms (counted with multiplicity) in the Goldman bracket between them. We also construct infinitely many pairs of length equivalent curves in any hyperbolic surface F of finite type. Our construction shows that given a self- intersecting geodesic x of F and any self-intersection point P of x, we get a sequence of such pairs.
279

Grothendieck Group Decategorifications and Derived Abelian Categories

McBride, Aaron January 2015 (has links)
The Grothendieck group is an interesting invariant of an exact category. It induces a decategorication from the category of essentially small exact categories (whose morphisms are exact functors) to the category of abelian groups. Similarly, the triangulated Grothendieck group induces a decategorication from the category of essentially small triangulated categories (whose morphisms are triangulated functors) to the category of abelian groups. In the case of an essentially small abelian category, its Grothendieck group and the triangulated Grothendieck group of its bounded derived category are isomorphic as groups via a natural map. Because of this, homological algebra and derived functors become useful in surprising ways. This thesis is an expository work that provides an overview of the theory of Grothendieck groups with respect to these decategorications.
280

Equivalence singulière à la Morita et la cohomologie de Hochschild singulière / Singular equivalence of Morita type and singular Hochschild cohomology

Wang, Zhengfang 07 December 2016 (has links)
L’objet de cette thèse est l’étude des catégories singulières des k-algèbres associatives surun anneau commutatif k. On développe la théorie de Morita pour les catégories singulières. Plus précisément, on propose une définition d’équivalence singulière à la Morita avec niveau, qui généralise la notion d’équivalence stable à la Morita introduite par Michel Broué. On montre qu’une équivalence dérivée de type standard induit une équivalence singulière à la Morita avec niveau. La deuxième partie de cette thèse est l’étude de la cohomologie de Hochschild singulière HH_sg(A,A) c’est-à-dire, l’espace des morphismes de A vers A[i] dans la catégorie singulière Dsg(A Aop) pour tous les nombres entiers i. Similaire à la cohomologie de Hochschild HH_(A,A), on montre que la cohomologie de Hochschild singulière HH_sg(A,A) est une algèbre de Gerstenhaber et donne une interprétation pour le crochet de Lie sur HH_sg(A,A) du point de vue de la théorie de PROP. On peut associer un complexe de cochaînes, qu’on appelle complexe de cochaînes de Hochschild singulières, C_sg(A,A) qui calcule la cohomologie de Hochschild singulière HH_sg(A,A). Alors on étudie une structure algébrique supérieure (e.g. l’algèbre de B1) sur C_sg(A,A) et propose une version singulière d’une conjecture de Deligne. L’objet de la troisième partie de cette thèse est de montrer que la structure d’algèbre de Gerstenhaber sur la cohomologie de Hochschild singulière est invariante par équivalences dérivées et équivalences singulières à la Morita avec niveau. L’idée de cette démonstration est analogue à l’approche développée par Keller lorsqu’il démontre que la structure d’algèbre de Gerstenhaber sur la cohomologie de Hochschild est invariante par équivalences dérivées. Similaire à la démonstration par Keller, on réalise HH_sg(A,A) avec le crochet de Lie comme une algèbre de Lie graduée du groupe algébrique gradué associé au groupe de Picard singulière sgDPic(A). / In this thesis, we are concerned with some aspects of singular categories of unitalassociative k-algebras over a commutative ring k. First, we develop a Morita theory for singular categories. Analogous to the classical Morita theory, we propose a definition of singular equivalence of Morita type with level. This follows and generalizes a definition of stable equivalence of Morita type introduced by Michel Broué. A derived equivalence of standard type induces a singular equivalence of Morita type with level. Second, we study the Hom-space from A to A[i] in the singular category Dsg(AkAop) of the enveloping algebra AkAop, where A is an associative k-projective k-algebra and i is any integer. Recall that the i-th Hochschild cohomology group HHi(A,A) can be realized as the Hom-space from A to A[i] in the bounded derived category Db(A k Aop). From this motivation, we call HomDsg(AkAop)(A,A[i]) the i-th singular Hochschild cohomology group and denote this group by HHi sg(A,A). Analogous to the Hochschild cohomology ring HH_(A,A), we prove that there is a Gerstenhaber algebra structure on the singular Hochschild ring HH_sg(A,A) and provide an interpretation of the Lie bracket from the point of view of PROP theory. We also associate a cochain complex, which we call singular Hochschild cochain complex, C_sg(A,A) to the singular Hochschild cohomology. Thenwe study the higher algebraic structures (e.g. B1-algebra) on C_sg(A,A) and propose asingular version of the Deligne conjecture. Following Keller’s approach which was developed for derived equivalences, we establish the invariance of the Gerstenhaber algebra structure which we defined on the singular Hochschild cohomology under singular equivalence of Morita type with level. In this proof, we define the singular derived Picard group sgDPic(A) of an associative algebra A and develop what we call a singular infinitesimal deformation theory. Then we realize HH_sg(A,A) as the graded Lie algebra of the ‘graded algebraic group’ associated to sgDPic(A).

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