We consider a family of generalized Procrustes problems. In this class of problems, one aims at aligning a set of vectors to a given second set of vectors. The distance between both sets is measured in the q norm, and for the alignment, isometries with respect to the p norm are allowed. In contrast to the classical Procrustes problem with p = q = 2, we allow p and q to differ. We will see that it makes a difference whether the problem is real or cast over the complex field. Therefore, we discuss the solutions for p = 2 separately for these cases. We show that all the real cases can be solved efficiently. Most of the complex cases can up to now only be solved approximately in polynomial time, but we show the existence of polynomial time algorithms for q ∈ {2, 4, ∞}. Computational experiments illustrate the suggested algorithms.

We consider a family of generalized Procrustes problems. In this class of problems, one aims at aligning a set of vectors to a given second set of vectors. The distance between both sets is measured in the q norm, and for the alignment, isometries with respect to the p norm are allowed. In contrast to the classical Procrustes problem with p = q = 2, we allow p and q to differ. We will see that it makes a difference whether the problem is real or cast over the complex field. Therefore, we discuss the solutions for p = 2 separately for these cases. We show that all the real cases can be solved efficiently. Most of the complex cases can up to now only be solved approximately in polynomial time, but we show the existence of polynomial time algorithms for q ∈ {2, 4, ∞}. Computational experiments illustrate the suggested algorithms.

This paper deals with the symmetric approximation numbers as well as the other types of s-numbers. Concerning the s-numbers in the Banach spaces, namely the app- roximation numbers the Kolmogorov numbers and the Gelfand numbers, we present a few of possible definitions and some of their properties. We present the symmetric approximation numbers and their relation to the other s-numbers. We also focus on the s-numbers in the quasi-Banach spaces. The situation is a bit different, as we can not use the Hahn-Banach Theorem. Therefore some of the previous definitions and properties can not be retained. Moreover we define the symmetric approximation num- bers in the quasi-Banach spaces and discuss the problematics of this definition. Finally, we deal with the Carl's inequality regarding the entropy numbers and the s-numbers. We derive the proof for the symmetric approximation numbers in both Banach and quasi-Banach case. 1

Made available in DSpace on 2014-11-10T11:09:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-21Bitstream added on 2014-11-10T11:57:46Z : No. of bitstreams: 1 000790735.pdf: 1590232 bytes, checksum: 5297d173df2a824606d944767eb1610c (MD5) / O principal objetivo deste trabalho consiste na produção de um referencial teórico relacionado aos conceitos de ponto fixo, que possibilite, aos alunos do Ensino Médio, o desenvolvimento de habilidades e competências relacionadas à Matemática. Neste trabalho são colocadas abordagens contextualizadas e proposições referentes às noções de ponto fixo nas principais funções reais (afim, quadrática, modular, dentre outras) e sua interpretação geométrica. São abordados de maneira introdutória os conceitos do teorema do ponto fixo de Brouwer, o teorema do ponto fixo de Banach e o método de resolução de equações por aproximações sucessivas / The main objective of this work is to produce a theoretical concepts related to fixed point, enabling, for high school students, the development of skills and competencies related to Mathematics. This work placed contextualized approaches and proposals relating to notions of fixed point in the main real functions (affine, quadratic, modular, among others) and its geometric interpretation. Are approached introductory concepts of the fixed point theorem of Brouwer's, fixed point theorem of Banach and the method of solving equations by successive approximations

Made available in DSpace on 2015-05-15T11:46:05Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 865721 bytes, checksum: 3cb3fb14f515822a2db03f7945b5427a (MD5) Previous issue date: 2013-04-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents a study of Cohen strongly summing operators under the viewpoint of the theory of multilinear operators ideals and polynomial ideals. Furthermore, we introduce two new classes that generalize the concept of multilinear operators and polynomials of this nature, namely multiple Cohen strongly summing operators and Cohen strongly summing operators at a given point. We show that the new classes defined, as well as the previous classes, form normed ideals of operators/polynomials and that the class of multiple Cohen strongly summing operators forms a Banach ideal. We also show that the construction of the class of multiple Cohen strongly summing operators provides a holomorphy type and a coherent and compatible sequence of ideals. / Neste trabalho apresentamos um estudo dos operadores Cohen fortemente somantes sob o ponto de vista da teoria de ideais de operadores e polinômios. Além disso, introduzimos duas novas classes de operadores que generalizam o conceito de operadores multilineares e polinômios desta natureza, a saber, os operadores múltiplo Cohen fortemente somantes e os operadores Cohen fortemente somantes num dado ponto. Mostramos que as novas classes definidas, como as anteriores, formam ideais normados de operadores/polinômios e que os operadores múltiplo Cohen fortemente somantes formam um ideal de Banach. Também mostramos que a construção da classe dos operadores múltiplo Cohen fortemente somantes fornece um tipo de holomorfia e uma sequência coerente e compatível de ideais.

Motivated by results of linear algebra over fields, rings and tropical semirings, we present a systematic way to understand the behaviour of matrices with entries in an arbitrary semiring. We focus on three closely related problems concerning the row and column spaces of matrices. This allows us to isolate and extract common properties that hold for different reasons over different semirings, yet also lets us identify which features of linear algebra are specific to particular types of semiring. For instance, the row and column spaces of a matrix over a field are isomorphic to each others' duals, as well as to each other, but over a tropical semiring only the first of these properties holds in general (this in itself is a surprising fact). Instead of being isomorphic, the row space and column space of a tropical matrix are anti-isomorphic in a certain order-theoretic and algebraic sense. The first problem is to describe the kernels of the row and column spaces of a given matrix. These equivalence relations generalise the orthogonal complement of a set of vectors, and the nature of their equivalence classes is entirely dependent upon the kind of semiring in question. The second, Hahn-Banach type, problem is to decide which linear functionals on row and column spaces of matrices have a linear extension. If they all do, the underlying semiring is called exact, and in this case the row and column spaces of any matrix are isomorphic to each others' duals. The final problem is to explain the connection between the row space and column space of each matrix. Our notion of a conjugation on a semiring accounts for the different possibilities in a unified manner, as it guarantees the existence of bijections between row and column spaces and lets us focus on the peculiarities of those bijections. Our main original contribution is the systematic approach described above, but along the way we establish several new results about exactness of semirings. We give sufficient conditions for a subsemiring of an exact semiring to inherit exactness, and we apply these conditions to show that exactness transfers to finite group semirings. We also show that every Boolean ring is exact. This result is interesting because it allows us to construct a ring which is exact (also known as FP-injective) but not self-injective. Finally, we consider exactness for residuated lattices, showing that every involutive residuated lattice is exact. We end by showing that the residuated lattice of subsets of a finite monoid is exact if and only if the monoid is a group.

Orientador: German Jesus Lozada Cruz / Banca: Cosme Eustaquio Rubio Mercedes / Banca: Rita de Cássia Pavani Lamas / Resumo: O principal objetivo deste trabalho consiste na produção de um referencial teórico relacionado aos conceitos de ponto fixo, que possibilite, aos alunos do Ensino Médio, o desenvolvimento de habilidades e competências relacionadas à Matemática. Neste trabalho são colocadas abordagens contextualizadas e proposições referentes às noções de ponto fixo nas principais funções reais (afim, quadrática, modular, dentre outras) e sua interpretação geométrica. São abordados de maneira introdutória os conceitos do teorema do ponto fixo de Brouwer, o teorema do ponto fixo de Banach e o método de resolução de equações por aproximações sucessivas / Abstract: The main objective of this work is to produce a theoretical concepts related to fixed point, enabling, for high school students, the development of skills and competencies related to Mathematics. This work placed contextualized approaches and proposals relating to notions of fixed point in the main real functions (affine, quadratic, modular, among others) and its geometric interpretation. Are approached introductory concepts of the fixed point theorem of Brouwer's, fixed point theorem of Banach and the method of solving equations by successive approximations / Mestre

Le but de cette thèse est d'élaborer des méthodes d'éclatement basées sur les distances de Bregman pour la résolution d'inclusions monotones composites dans les espaces de Banach réels réflexifs. Ces résultats nous permettent d'étendre de nombreuses techniques, jusqu'alors limitées aux espaces hilbertiens. De plus, même dans le cadre restreint d'espaces euclidiens, ils donnent lieu à de nouvelles méthodes de décomposition qui peuvent s'avérer plus avantageuses numériquement que les méthodes classiques basées sur la distance euclidienne. Des applications numériques en traitement de l'image sont proposées. / The goal of this thesis is to design splitting methods based on Bregman distances for solving composite monotone inclusions in reflexive real Banach spaces. These results allow us to extend many techniques that were so far limited to Hilbert spaces. Furthermore, even when restricted to Euclidean spaces, they provide new splitting methods that may be more avantageous numerically than the classical methods based on the Euclidean distance. Numerical applications in image processing are proposed.

In dieser Arbeit möchte ich dem Wesen des Auswahlaxioms auf den Grund gehen und verstehen, inwieweit es problematisch sein könnte, es zu benutzen, aber auch wie nützlich es ist, dieses mächtige Instrument als Mathematiker zu besitzen.

The traditional first-order analysis in Euclidean spaces relies on the Sobolev spaces W1,p(Ω), where Ω ⊂ Rn is open and p ∈ [1, ∞].The Sobolev norm is then defined as the sum of Lp norms of a function and its distributional gradient.We generalize the notion of Sobolev spaces in two different ways. First, the underlying function norm will be replaced by the “norm” of a quasi-Banach function lattice. Second, we will investigate functions defined on an abstract metric measure space and that is why the distributional gradients need to be substituted. The thesis consists of two papers. The first one builds up the elementary theory of Newtonian spaces based on quasi-Banach function lattices. These lattices are complete linear spaces of measurable functions with a topology given by a quasinorm satisfying the lattice property. Newtonian spaces are first-order Sobolev-type spaces on abstract metric measure spaces, where the role of weak derivatives is passed on to upper gradients. Tools such asmoduli of curve families and the Sobolev capacity are developed, which allows us to study basic properties of the Newtonian functions.We will see that Newtonian spaces can be equivalently defined using the notion of weak upper gradients, which increases the number of techniques available to study these spaces. The absolute continuity of Newtonian functions along curves and the completeness of Newtonian spaces in this general setting are also established. The second paper in the thesis then continues with investigation of properties of Newtonian spaces based on quasi-Banach function lattices. The set of all weak upper gradients of a Newtonian function is of particular interest.We will prove that minimalweak upper gradients exist in this general setting.Assuming that Lebesgue’s differentiation theoremholds for the underlyingmetricmeasure space,wewill find a family of representation formulae. Furthermore, the connection between pointwise convergence of a sequence of Newtonian functions and its convergence in norm is studied.