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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.
1

Superfícies mínimas e curvatura de gauss de conóides em espaços de finsler com (α,β) - métricas / Minimal surfaces and gauss curvature of conoid in finsler spaces with (α,β) - metrics

Daza, John Elber Gómez 28 March 2014 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-11-14T20:38:05Z No. of bitstreams: 2 Dissertação - John Elber Gómez Daza - 2014.pdf: 3536612 bytes, checksum: f7e71dbc62f224cd024c41999d7b2f0c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-11-18T15:40:54Z (GMT) No. of bitstreams: 2 Dissertação - John Elber Gómez Daza - 2014.pdf: 3536612 bytes, checksum: f7e71dbc62f224cd024c41999d7b2f0c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-11-18T15:40:54Z (GMT). No. of bitstreams: 2 Dissertação - John Elber Gómez Daza - 2014.pdf: 3536612 bytes, checksum: f7e71dbc62f224cd024c41999d7b2f0c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-03-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / We consider(α,β)−metric F=αφ(β α), whereα is the euclidean metric,φ is a smooth positive function on a symmetric interval I=(−b0,b0) and β is a 1-form with the norm b,0 ≤b<b0, on the Finsler manifoldM. We study the minimal surfaces on these spaces with respect to the Holmes-Thompson volume form and we present the equation that characterize the minimal hypersurfaces in general Minkowski space. We prove that the conoids in three-dimensional space are minimal if and only if is a helicoid or a plane, also we show that the Gauss curvature of conoid in Randers-Minkowski 3-space is not always nonpositive on minimal surfaces. Finally, an ordinary differential equation that characterizes minimal surfaces of revolution and an example of minimal surface of rotationaregiven. / Neste trabalho consideramos (α,β)−métricas do tipo F=αφ(β α), ondeα é a métrica euclidiana,φ é uma função positiva suave sobre um intervalo simétrico I=(−b0,b0) e β é uma 1-forma de norma b,0 ≤ b < b0, sobre uma variedade de Finsler M. Estudamos superfícies mínimas nestes espaços (M,F) com respeito à forma volume de Holmes-Thompson e apresentamos uma equação que caracteriza as hipersuperfícies mínimasemumespaçogeral(α,β)−Minkowski.Mostramosqueosconóidesnoespaço tridimensional comβ na direção do eixo ˜y3 são mínimas se, e somente se, é um helicóide ou um plano, provamos também que a curvatura de Gauss do conóide em um espaço tridimensional de Randers-Minkowski pode ser positiva em superfícies mínimas. Finalmente apresentamos uma equação diferencial ordinária que caracteriza superfícies mínimas de rotação eum exemplo de superfíciemínimade rotação.
2

Étude des sous-variétés dans les variétés kählériennes, presque kählériennes et les variétés produit / Study of submanifolds of Kaehler manifolds, nearly Kaehler manifolds and product manifolds

Moruz, Marilena 03 April 2017 (has links)
Cette thèse est constituée de quatre chapitres. Le premier contient les notions de base qui permettent d'aborder les divers thèmes qui y sont étudiés. Le second est consacré à l'étude des sous-variétés lagrangiennes d'une variété presque kählérienne. J'y présente les résultats obtenus en collaboration avec Burcu Bektas, Joeri Van der Veken et Luc Vrancken. Dans le troisième, je m'intéresse à un problème de géométrie différentielle affine et je donne une classification des hypersphères affines qui sont isotropiques. Ce résultat a été obtenu en collaboration avec Luc Vrancken. Et enfin dans le dernier chapitre, je présente quelques résultats sur les surfaces de translation et les surfaces homothétiques, objet d'un travail en commun avec Rafael López. / Abstract in English not available
3

Superfícies de translação Weingarten lineares nos espaços euclidiano e Lorentz-Minkowski

Ferreira, Thiago Lucas da Silva, 92-99320-5663 14 December 2016 (has links)
Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-06-19T17:00:58Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertação-Thiago Lucas-FINAL.pdf: 424556 bytes, checksum: 504bc5cad61e90dcf5cfc403f099b634 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-06-19T17:01:10Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertação-Thiago Lucas-FINAL.pdf: 424556 bytes, checksum: 504bc5cad61e90dcf5cfc403f099b634 (MD5) / Made available in DSpace on 2018-06-19T17:01:10Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertação-Thiago Lucas-FINAL.pdf: 424556 bytes, checksum: 504bc5cad61e90dcf5cfc403f099b634 (MD5) Previous issue date: 2016-12-14 / In this dissertation we will present a demonstration that a linear Weingarten translation surface in Euclidean space and Lorentz-Minkowski space should have constant mean curvature or constant Gaussian curvature. The work is based on the article "Translation surfaces of linear Weingarten type" Antonio Bueno and Rafael López. / Nesta dissertação apresentaremos uma demonstração de que uma superfície de translação Weingarten linear no espaço euclidiano e no espaço Lorentz- Minkowski deve ter curvatura média constante ou curvatura de Gauss constante. O trabalho é baseado no artigo "Translation surfaces of linear Weingarten type"de Antonio Bueno e Rafael López.

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