Thesis (M.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 40-43). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [47]-48).

No description available.

Science and Technology Education / M.Sc. (Chemical Education)

Given a closed surface Sg of genus g, a mapping class f in \MCG(Sg) is said to be pseudo-Anosov if it preserves a pair of transverse measured foliations such that one is expanding and the other one is contracting by a number \lambda(f). The number \lambda(f) is called a stretch factor (or dilatation) of f. Thurston showed that a stretch factor is an algebraic integer with degree bounded above by 6g-6. However, little is known about which degrees occur. Using train tracks on surfaces, we explicitly construct pseudo-Anosov maps on Sg with orientable foliations whose stretch factor \lambda has algebraic degree 2g. Moreover, the stretch factor \lambda is a special algebraic number, called Salem number. Using this result, we show that there is a pseudo-Anosov map whose stretch factor has algebraic degree d, for each positive even integer d such that d≤g. Our examples also give a new approach to a conjecture of Penner.

Thesis (Ph. D. in Mathematics)--Vanderbilt University, Aug. 2006. / Title from title screen. Includes bibliographical references.

Science and Technology Education / M.Sc. (Chemical Education)

Computational group theory deals with the design, analysis and computer implementation of algorithms for solving computational problems involving groups, and with the applications of the programs produced to interesting questions in group theory, in other branches of mathematics, and in other areas of science. This thesis describes an implementation of a proposal for a Soluble Quotient Algorithm, i.e. a description of the algorithms used and a report on the findings of an empirical study of the behaviour of the programs, and gives an account of an application of the programs. The programs were used for the construction of soluble groups with interesting properties, e.g. for the construction of soluble groups of large derived length which seem to be candidates for groups having efficient presentations. New finite soluble groups of derived length six with trivial Schur multiplier and efficient presentations are described. The methods for finding efficient presentations proved to be only practicable for groups of moderate order. Therefore, for a given derived length soluble groups of small order are of interest. The minimal soluble groups of derived length less than or equal to six are classified.

Orientador: Alexandre Ananin / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatisitca e Computação Cientifica / Made available in DSpace on 2018-08-07T02:11:51Z (GMT). No. of bitstreams: 1 Ferreira_CarlosHenriqueGrossi_D.pdf: 2079010 bytes, checksum: d2897485f4c4ad44b6ca3016ebc4a4f6 (MD5) Previous issue date: 2006 / Resumo: Esta tese possui quatro partes. A primeira parte apresenta uma construção que permite abordar todas as geometrias clássicas sob um mesmo ponto de vista. Utilizando tal abordagem, expressamos e caracterizamos, de modo simples e isento de coordenadas, vários aspectos destas geometrias, tais como geodésicas distâncias, transporte paralelo, tensores de curvatura e curvaturas seccionais. Esperamos, assim, unificar e facilitar o estudo das geometrias clássicas, evitando a introdução de vários ¿modelos¿ para uma mesma geometria (como é o caso dos modelos de Poincaré, de Siegel e de Klein para as geometrias hiperbólicas) bem como evitando a descrição de métricas através de sistemas de coordenadas específicos. A segunda parte consiste em aplicar as ferramentas desenvolvidas anteriormente para o caso específico da geometria hiperbólica complexa. O foco central é o estudo de configurações de um número pequeno de pontos. Deste modo estudamos propriedades básicas de objetos elementares tais como linhas projetivas, geodésicas e bissetores. Estas propriedades provaram-se essenciais com relação ao nosso principal objetivo, o estudo de grupos discretos de isometrias do plano hiperbólico complexo. A terceira parte consiste em uma versão do Teorema Poliedral de Poincaré em que as exigências sobre a tesselação são suficientemente locais. Além disso, buscamos para o referido Teorema condições simples e verificáveis na prática. A versão apresentada pode ser aplicada em geometrias de curvatura não-constante, nas quais n¿ao podemos explorar, por exemplo, os conceitos de convexidade. Por fim, a quarta parte é um artigo produzido em colaboração com os professores Alexandre Ananin e Nikolai Goussevskii. Neste artigo, novos exemplos de variedades com estrutura hiperbólica complexa s¿ao apresentados, resolvendo alguns problemas da área / Abstract: This thesis consists of four parts. The first part consists of a construction interpreting all classic geometries in the same way. With this construction, we express and characterize various aspects of these geometries, such as geodesics, distances, parallel displacement, curvature tensors, and sectional curvatures, in a simple coordinate-free way. We believe that this approach can unify and simplify the study of classic geometries escaping the use of several ¿models¿ for the same geometry (as Poincaré¿s, Siegel¿s, and Klein¿s models of hyperbolic geometry) as well as avoiding descriptions of metrics in specific coordinates. In the second part we apply the previously developed tools to the case of complex hyperbolic geometry. The guideline is the study of finite configurations of points. From this point of view, we study basic properties of elementary geometric objects such as projective lines, geodesics, and bisectors. These properties turned out to be crucial for our central purpose, the study of discrete groups of isometries of the complex hyperbolic plane. The third part consists of a version of Poincaré¿s Polyhedron Theorem where the conditions concerning the tessellation are sufficiently local. Also, we consider conditions that are simple and verifiable in practice. The proposed theorem can be applied in the case of geometries of non-constant curvature when some concepts, as those of convexity, are not applicable. Finally, the fourth part is an article written in collaboration with professor Alexandre Ananin and professor Nikolai Goussevskii. In this article, new series of examples of complex hyperbolic manifolds are constructed, solving some problems in the area / Doutorado / Geometria / Doutor em Matemática

Orientador: Dessislava Hristova Kochloukova / Dissertação (mestrado) - Universidade Estadual de Campinas. Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-04T11:05:09Z (GMT). No. of bitstreams: 1 Kitani_PatriciaMassae_M.pdf: 1013676 bytes, checksum: 794e7e67a9a90f759b790877a816b7f6 (MD5) Previous issue date: 2005 / Resumo: Este trabalho consistiu no estudo das aplicações de topologia algébrica (recobrimentos, teorema de Van Kampen) em teoria de grupos e também, no estudo detalhado do resultado de R. Bieri, R. Strebel [Proc. London Math. Soc. (3) 41 (1980), no. 3, 439¿464], que para um grupo G do tipo FP2, ou G contém subgrupo livre não cíclico ou para qualquer subgrupo normal N C G tal que Q = G/N é abeliano, N/[N,N] é um ZQ-módulo manso via conjugação. A definição de módulo manso usa o invariante de Bieri-Strebel §A(Q), nesse caso A = N/[N,N] / Abstract: This work consisted of the study of the applications of algebraic topology (covering maps, Van Kampen theorem) in group theory and also, in the detailed study of a result of R. Bieri, R. Strebel [Proc. London Math. Soc. (3) 41 (1980), no. 3, 439¿464], that for a group G of type FP2, either G has a free non-cyclic subgroup or for any normal subgroup N C G such that Q = G/N is abelian, N/[N,N] is a tame ZQ-module where Q acts via conjugation. The definition of tame module uses the Bieri-Strebel invariant §A(Q), in this case A = N/[N,N] / Mestrado / Algebra / Mestre em Matemática