Étant donnée une fonction lisse ˜ f définie sur un voisinage de la sphère euclidienne de dimension n dans la boule, peut-on l’étendre en une fonction définie sur la boule bordée par la sphère, de manière à ce que l’extension n’ait aucun point critique ? Cette thèse propose d’étudier cette question, en supposant que la restriction de ˜ f à la sphère, notée f, est Morse. Ce problème a été introduit pour la première fois par Blank et Laudenbach en1970, et a aussi été posé par Arnol’d en 1981. Nous donnons une condition nécessaire d’extension sans points critiques qui s’appuie sur le complexe de Morse de la fonction f, et de la répartition des points critiques de f en deux ensembles : ceux dont la dérivée normale est négative et ceux dont la dérivée normale est positive. Cette condition nécessaire permet alors de donner un cadre algébrique à ce problème venant de la topologie différentielle et s’appuie principalement sur lesgrandes théories de la deuxième moitié du XXème siècle, à savoir celle des cobordismes de Thom,Smale, Milnor etc. Elle permet notamment de donner des conditions nécessaires et suffisantesdans certains cas plus restrictifs, et donne lieu à une condition nécessaire plus faible qui présentel’intérêt d’être calculable.Le point de départ des résultats est celui de Barannikov, qui le premier a traduit le problèmed’extension de fonction avec des conditions de dérivées normales en un problème de chemin defonctions générique qui ne présente pas de singularité globale. / Given a smooth function ˜ f defined on a neighborhood of the euclidian sphere of dimension n in the ball, is it possible to extend it to a function defined on the ball which has no critical points ? This thesis studies this question, assuming the f, the restriction of ˜ f to the sphere, is Morse.This problem was first introduced by Blank and Laudenbach in 1970. We give a necessary condition of extension without critical points that is based on Morsehomology and the repartition of the critical set of f into two sets : the set of points whosenormal derivative to the sphere interior to the ball is negative and the set of points whosenormal derivative is positive. This necessary condition is of algebraic nature and uses great theories of the second half of the XXth century, namely cobordism theory of Thom, Smale,Milnor etc. It also leads to a sufficient condition in some interesting cases, and to a weaker necessary condition for a general function ˜ f which is easily computable.The point-of-view is the one of Barannikov, who was the first to tackle this problem bymeans of considerations about path of functions

Made available in DSpace on 2016-04-27T16:58:04Z (GMT). No. of bitstreams: 1 dissertacao_marcos_roberto_celestino.pdf: 366226 bytes, checksum: ce28d8d3d5ba303737754934ffc55b37 (MD5) Previous issue date: 2000-10-09 / The researches on teaching-learning of the Linear Algebra come "globally" obtaining a larger attention of the investigators in Mathematical Education. This work objectified to collect and to present the Brazilian authors researches on the teaching-learning of the Linear Algebra, accomplished in the 90's decade. The Brazilian contribution was analyzed and inserted in the context of the researches done in world level in the area. It was ended that, although there was a small number of Brazilian works, these presented coherent results with the "world" researches, sometimes contributing with unpublished results; besides, they aimed suggestions for another investigations in the area of teaching-learning of the Linear Algebra / As pesquisas sobre ensino-aprendizagem da Álgebra Linear vêm obtendo mundialmente uma maior atenção dos investigadores em Educação Matemática. Este trabalho objetivou coletar e apresentar as pesquisas de autores brasileiros sobre o ensino-aprendizagem da Álgebra Linear, realizadas na década de 90. A contribuição brasileira foi analisada e inserida no contexto das pesquisas feitas em nível mundial na área. Concluiu-se que, embora houvesse um pequeno número de obras brasileiras, estas apresentavam resultados coerentes com as pesquisas mundiais , algumas vezes contribuindo com resultados inéditos; além disso, apontavam sugestões para outras investigações na área de ensino-aprendizagem da Álgebra Linear

Made available in DSpace on 2016-04-27T16:58:10Z (GMT). No. of bitstreams: 1 dissertacao_zoraide_lucia_padredi.pdf: 669980 bytes, checksum: da1bfe1b4836affc460febdadf61ae40 (MD5) Previous issue date: 2003-12-19 / The purpose of this work is to investigate meta resources suggested by teachers, to contribute to the students better comprehension of the notion of basis of vectorial space. In doing so, six teachers were interviewed. The analysis of the interviews supported by Dorier, Robert, Robinet and Rogalski ideas about meta lever and the Harel s principles for the teaching and learning of Linear Algebra. The conclusion presents different Meta resources that could became meta lever for students better comprehension / Este trabalho objetivou investigar recursos meta sugeridos por professores para facilitar a compreensão da noção de base de um espaço vetorial. Foram realizadas entrevistas com 6 professores universitários. A análise dessas entrevistas utilizou como suporte teórico os trabalhos do grupo francês composto por Dorier, Robert, Robinet e Rogalski, sobre alavancas meta , assim como os princípios de Harel para ensino e aprendizagem da Álgebra Linear. Concluiu-se, com a indicação de diversos recursos meta que são passíveis de se tornarem alavancas para a compreensão dos alunos

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-08-28T21:39:51Z No. of bitstreams: 2 TCC APLICAÇÕES DE AL PROFMAT 2013.pdf: 455396 bytes, checksum: b39442c76a5d76a386c0794f86f1c9da (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-08-28T21:39:51Z (GMT). No. of bitstreams: 2 TCC APLICAÇÕES DE AL PROFMAT 2013.pdf: 455396 bytes, checksum: b39442c76a5d76a386c0794f86f1c9da (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-04-12 / This work shows the importance of the Linear Algebra and in particular of the theory of Matrices and Linear Systems to solve practical problems in various areas. We show examples of Applications of Linear Systems in closed and open models of Leontief in Economics, in closed circuits (Law Kirccho ) and in projects of construction of steel structures. / O presente trabalho mostra a importância da Álgebra Linear e em particular da teoria da Matrizes e Sistemas Lineares para resolver problemas práticos em diversas áreas. Mostramos exemplos de aplicações dos Sistemas Lineares nos modelos fechado e aberto de Leontief na área de Economia, em circuitos elétricos fechados (Lei de Kirccho ) e em projetos de construção de estruturas metálicas.

Made available in DSpace on 2016-04-27T16:58:32Z (GMT). No. of bitstreams: 1 Michele Viana Debus de Franca.pdf: 12562949 bytes, checksum: ad73cab11181e37cb89082b315501ffe (MD5) Previous issue date: 2007-10-19 / Secretaria da Educação do Estado de São Paulo / This study treats questions related to the learning of Linear Algebra concepts in in the superior education. The research involved the design of activities on the concepts of vector coordinates, linear dependency, base and linear transformation on the plane, articulating different records in a Dynamic Geometry environment. It was intended to investigate in what measure a geometric treatment and the articulation among representation registers (algebraic, graphical and geometric), assisted by the Cabri-Géomètre environment, influence in the conceptions of students who have already attended the discipline of Linear Algebra. The theoretical bases of this study are the Duval s theory of Semiotics Representation Registers (1995, 2000, 2005) and the Vergnaud s theory of the Conceptual Fields (1990, 1997, 1998). Based on the teaching experiment methodology (Steffe & Thompson, 2000), exploration activities of different representations for the concepts already mentioned were conceived. Eighteen third grade Mathematic students from a Private University from the city of São Paulo participated in the experiment. Although the students tried to reproduce a symbolic algebraic register, they did not show sense domain, what was not foreseen in the design of activities. Even so, based on the results, we can identify the individual s evolution on the understanding of the concepts, as well as a wider domain of the graphical, algebraic and geometric representations, carrying through conversions in both directions, to make them collate with false invariants, which they possessed, and compelling them to question and to explain notions. The Dynamic Geometry environment provided positive effects in the students resolution strategies, providing means of experimental validation of the theorem-in-action and leading them to explicitate and rediscuss the involved notions, from the different aspects evoked in the representations / Este estudo trata de questões relativas à aprendizagem de conceitos de Álgebra Linear no ensino superior. A pesquisa envolveu o design de atividades sobre os conceitos de coordenadas de vetores, dependência linear, base e transformação linear no plano, articulando diferentes registros em um ambiente de Geometria Dinâmica. Objetivou-se investigar em que medida um tratamento geométrico e a articulação entre registros de representação (algébrico, gráfico e geométrico), auxiliados pelo ambiente Cabri-Géomètre, influenciam nas concepções de estudantes que já cursaram a disciplina de Álgebra Linear. As bases teóricas deste estudo são os Registros de Representação Semiótica de Duval (1995, 2000, 2005) e a Teoria dos Campos Conceituais de Vergnaud (1990, 1997, 1998). Com base na metodologia de experimento de ensino (Steffe & Thompson, 2000), foram concebidas atividades de exploração de diferentes representações para os conceitos já mencionados. Participaram do experimento 18 alunos de uma turma de terceiro ano de Licenciatura em Matemática de uma universidade particular da cidade de São Paulo. Apesar de os estudantes tentarem reproduzir um registro simbólico-algébrico, não demonstraram domínio de sentido, o que não estava previsto no design das atividades. Ainda assim, com base nos resultados, podemos identificar evoluções dos sujeitos na compreensão dos conceitos, bem como um domínio mais amplo das representações gráfica, algébrica e geométrica, realizando conversões em ambos os sentidos, servindo para fazer com que os mesmos fossem confrontados com falsos invariantes os quais eles possuíam e obrigando-os a questioná-los e explicitar noções. O ambiente de Geometria Dinâmica proporcionou efeitos positivos nas estratégias de resolução dos estudantes, fornecendo meios de validação experimental de teoremas-emação e levando-os a explicitar e rediscutir as noções envolvidas, a partir dos diferentes aspectos evocados nas representações

Made available in DSpace on 2016-04-27T16:58:47Z (GMT). No. of bitstreams: 1 Joelma Iamac Nomura.pdf: 747082 bytes, checksum: 187c2a106fc6bae9b62005a0ba6e1c7e (MD5) Previous issue date: 2008-10-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research included in the current project called In Search of propitious situations for learning basic concepts of Linear Algebra of Group's Studies of Education Algebraic (GPEA) of the Pontifical Catholic University of São Paulo (PUC-SP), proposes find elements that meet issues inherent in this research: Why and how should be tauch the discipline Linear Algebra in a graduate of Electrical Engineering? The choice of this subject is justified by the importance of Linear Algebra in the disciplines that make up a course in Electrical Engineering and the latent need of a change of focus given by teachers who teach the discipline. Therefore, we want to bring elements that justify the reformulation of the course that work with mathematical subjects such as Linear Algebra with graduations in this profile. The results were obtained through bibliographic searches, official documents applying for the courses of Electrical Engineering, interviews with teachers of graduation and applied exercises cited in the interviews. For its analysis, we sought in Anthropological Theory of the Didactic of Chevallard (1999), articulate the various concepts which are exposed in the triad object-person-institution. Among the results, we see that the learning of concepts of Linear Algebra as Matrix, Linear Systems and Linear Transformation is geared to existing relationships with others disciplines such as Electrical Circuits, Signal Processing, Electromagnetic Theory, among others. It also could identify the search for the formation of the conceptual and general engineer for that prime mathematical tied to search. We thus getting information to reply to our original question: Why does the Linear Algebra should be tauch in a graduate of Electrical Engineering? But how education could be directed? After the analysis of the gotten information, we perceive that the anticipation of certain content of the graduation could be worked through examples offered in current books of Linear Algebra. Another suggestion, pointing in the speech of teachers, refers to the integrated projects that address the interdisciplinary inherent in this course / Esta pesquisa inserida no atual projeto denominado Em busca de situações propícias para a aprendizagem de conceitos básicos de Álgebra Linear do Grupo de Estudos de Educação Algébrica (GPEA) da Pontifícia Universidade Católica de São Paulo (PUC-SP), propõe encontrar elementos que respondam às questões inerentes a esta investigação: Por que e Como deve ser lecionada a disciplina Álgebra Linear em uma graduação de Engenharia Elétrica? A escolha deste tema justifica-se pela importância da Álgebra Linear nas disciplinas que compõem um curso de Engenharia Elétrica e na necessidade latente de mudança de enfoque dado pelos professores que lecionam a disciplina. Assim, pretendemos trazer elementos que justifiquem a reformulação de cursos que trabalham com disciplinas matemáticas como a Álgebra Linear em graduações com este perfil. Os resultados foram obtidos através de pesquisas bibliográficas, documentos oficiais vigentes para os cursos de Engenharia Elétrica, entrevistas com professores desta graduação e exercícios aplicados citados nas entrevistas. Para sua análise, buscamos na Teoria Antropológica do Didático (TAD) de Chevallard (1999), articular as diversas noções expostas que constituem a tríade objeto-pessoa-instituição. Dentre os resultados obtidos, verificamos que a aprendizagem de conceitos de Álgebra Linear como Matrizes, Sistemas Lineares e Transformação Lineares está atrelada às relações existentes com outras disciplinas da graduação como Circuitos Elétricos, Processamento de Sinais, Teoria Eletromagnética, dentre outras. Também pudemos identificar a busca pela formação do engenheiro conceitual e generalista que prime por conhecimentos matemáticos vinculados à pesquisa. Estaríamos, assim, obtendo informações para responder a nossa pergunta inicial: Por que a Álgebra Linear deve ser lecionada em uma graduação de Engenharia Elétrica? Mas como poderia ser direcionado este ensino? Após análise das informações obtidas, percebemos que a antecipação de determinados conteúdos específicos da graduação poderia ser trabalhada através de exemplos propostos em livros atuais de Álgebra Linear. Outra sugestão, apontada no discurso dos professores, faz referência a projetos integrados que tratem a interdisciplinaridade inerente a este curso

<p>Ova doktorska disertacija uvodi nov pristup ispitivanju stabilnosti dinamičkih<br />sistema, korišćenjem teorije pseudospektra. Na taj način se postojeći pojam<br />stabilnosti profinjuje pojmom robusne stabilnosti, koji mnogo adekvatnije<br />opisuje realnu ekološku stabilnost. Razvijen je nov matematički alat za<br />izračunavanje indikatora stabilnosti, koji je zatim ilustrovan na primeru dva<br />ekosistema tla, sa po četiri uzorka, u četiri različita stadijuma razvoja.</p> / <p>This doctoral dissertation establishes a novel approach to the stability analysis of<br />dynamical systems, in terms of matrix pseudospectrum. In that manner, the existing<br />concept of stability has undergone essential refinement so as to give birth to the<br />concept of robust stability, which has the ability to capture the ecological stability at a<br />more adequate level. Additionally, within the framework of the dissertation, a new<br />mathematical tool for the stability indicators computation has been developed, which<br />has then been used to illustrate theoretical results in form of two soil ecosystems,<br />each of them sampled four times, all of them observed in four distinct stages of<br />evolution.</p>

The task of choosing a preconditioner M to use when solving a linear system Ax=b with iterative methods is often tedious and most methods remain ad-hoc. This thesis presents a randomized algorithm to make this chore less painful through use of randomized algorithms for estimating traces. In particular, we show that the preconditioner stability || I - M-1A ||F, known to forecast preconditioner quality, can be computed in the time it takes to run a constant number of iterations of conjugate gradients through use of sketching methods. This is in spite of folklore which suggests the quantity is impractical to compute, and a proof we give that ensures the quantity could not possibly be approximated in a useful amount of time by a deterministic algorithm. Using our estimator, we provide a method which can provably select a quality preconditioner among n candidates using floating operations commensurate with running about n log(n) steps of the conjugate gradients algorithm. In the absence of such a preconditioner among the candidates, our method can advise the practitioner to use no preconditioner at all. The algorithm is extremely easy to implement and trivially parallelizable, and along the way we provide theoretical improvements to the literature on trace estimation. In empirical experiments, we show the selection method can be quite helpful. For example, it allows us to create to the best of our knowledge the first preconditioning method for kernel regression which never uses more iterations over the non-preconditioned analog in standard settings.

This paper main goal is to introduce the basic language and programming styles of the mathematical software Mathematica (5.2), and applies it to solve problems in algebra, calculus, linear algebra, probability and statistics. We hope readers can enhance the interest of learning mathematics by the aid of software, verify the common theorem using the software, and solving mathematical problems.

Expert design knowledge is essential to develop a library of high-performance software. This includes how to implement and parallelize domain operations, how to optimize implementations, and estimates of which implementation choices are best. An expert repeatedly applies his knowledge, often in a rote and tedious way, to develop all of the related functionality expected from a domain-specific library. Expert knowledge is hard to gain and is easily lost over time when an expert forgets or when a new engineer starts developing code. The domain of dense linear algebra (DLA) is a prime example with software that is so well designed that much of experts' important work has become tediously rote in many ways. In this dissertation, we demonstrate how one can encode design knowledge for DLA so it can be automatically applied to generate code as an expert would or to generate better code. Further, the knowledge is encoded for perpetuity, so it can be reused to make implementing functionality on new hardware easier or it can be used to teach how software is designed to a non-expert. We call this approach to software engineering (encoding expert knowledge and automatically applying it) Design by Transformation (DxT). We present our vision, the methodology, a prototype code generation system, and possibilities when applying DxT to the domain of dense linear algebra. / text