Thèse--Faculté des sciences--Paris, 1882. / Notes bibliogr.

Thesis (doctoral)--Bonn, 1998. / Pages 10, 68 and 102 blank. Includes bibliographical references (p. 103-105).

Thesis (doctoral)--Rheinische Friedrich-Wilhelms-Universität Bonn, 1999. / Includes bibliographical references (p. 77-79).

archives@tulane.edu / There is a deep analogy between the theory of covering spaces and the theory offield extensions. Indeed, for many theorems about the Galois groups of field extensionsthere are analogous statements for the fundamental groups of covering spaces. Thepurpose of this thesis is to present an expository account of the connections betweenthese two useful concepts of algebra and geometry. / 1 / Dejun Zhang

Reproduction de : Thèse de doctorat : Mathématiques et leurs intéractions : Poitiers : 2008. / Titre provenant de l'écran-titre. Bibliogr. 45 réf.

A genus-two Riemann surface admits a canonical decomposition into Dirichlet polygons determined by its six Weierstrass points. All possible associated graphs are determined explicitly from circle packing problems, solved by systems of linear inequalities whose solutions determine a finite 6-dimensional polyhedral complex in 12-dimensional space. The 6-dimensional Moduli Space of genus-two Riemann surfaces inherits a canonical explicit decomposition into Euclidean polyhedra, giving new natural coordinates for the Teichmuller Space of all possible constant curvature geometries on a marked genus-two surface.

Thesis (Ph. D.)--Oregon State University, 2001. / Typescript (photocopy). Includes bibliographical references (leaves 33-35). Also available on the World Wide Web.

Thesis (doctoral)--Bonn, 1997. / Vita. Includes bibliographical references (p. 167-168).

Orientador: Celso Pascoli Bottura / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-07-22T22:47:58Z (GMT). No. of bitstreams: 1 Richter_CarlosMendes_M.pdf: 42112569 bytes, checksum: 2229a8747e522a3dd137578102cfd11a (MD5) Previous issue date: 1997 / Resumo: Este trabalho trata da análise de sistemas de controle monovariável e multivariável através das superficies de Riemann. É mostrado que a representação total destas superfícies abrange quatro dimensões, e novas representações são apresentadas em gráficos bidimensionais e tridimensionais. São propostas generalizações das representações já existentes, como lugar das raízes, diagramas de ganho, diagramas de Nyquist, de Bode e de Nichols, bem como dos respectivos diagramas complementares. São propostas novas formas de determinação de margens de fase e margens de ganho dos sistemas de controle monovariável, sendo estendidos os conceitos para o caso multivariável com base no critério generalizado de estabilidade de Nyquist. Para os casos monovariável e multivariável é mostrado que as margens de estabilidade podem ser determinadas diretamente sobre diversas representações de superficies de Riemann, e para diversos valores de ganho de realimentação negativa ou positiva, com tratamento único. São estabelecidos para os casos monovariável e multivariável novos gráficos de margens de estabilidade em função do ganho de realimentação negativa ou positiva, que são novas ferramentas de auxílio para análise e projeto de sistemas de controle realimentados / Abstract: This work deals with monovariable and multivariablecontrol systems analysisthrough Riemann surfaces. It is shown that a complete Riemann surface representation has dimension four, and new representations are presented in two-dimensional and three-dimensional plots. Generalizations ofthe existing representations, like root-Iocus, gain plots, Nyquist, Bode and Nichols diagrams, are proposed. New phase and gain margin determination methods are proposed for monovariable systems, and the concepts are extended to the multivariable case using the generalized Nyquist stability criterion. For both monovariable and multivariable cases, it is shown that gain and phase margins can be determined directly over several Riemann surface representations for several values of negative or positive feedback gains using an unique approach. New stability margin plots, functions of negative or positive feedback gain, are established, which are new aiding tools for analysis and synthesis of feedback control systems / Mestrado / Mestre em Engenharia Elétrica

In this thesis I will give a description of the Deligne–Mumford properad expressing it as the result of homotopically trivializing S¹ families of annuli (with appropriate compatibility conditions) in the properad of smooth Riemann surfaces with parameterized boundaries. This gives an analog of the results of Drummond-Cole and Oancea–Vaintrob in the setting of properads. We also discuss a variation of this trivialization which gives rise to a new partial compactification of Riemann surfaces relevant to the study of operations on symplectic cohomology.