Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-14T14:51:34Z No. of bitstreams: 2 Dissertação - Carlos Antônio Freitas da Silva - 2015.pdf: 659907 bytes, checksum: c43cf65b3e27833fcd6b4ab11eb79239 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-14T14:53:28Z (GMT) No. of bitstreams: 2 Dissertação - Carlos Antônio Freitas da Silva - 2015.pdf: 659907 bytes, checksum: c43cf65b3e27833fcd6b4ab11eb79239 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-05-14T14:53:28Z (GMT). No. of bitstreams: 2 Dissertação - Carlos Antônio Freitas da Silva - 2015.pdf: 659907 bytes, checksum: c43cf65b3e27833fcd6b4ab11eb79239 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this dissertation we will study Finsler Geometry. In particular, we will study Randers Geometry that which can be viewed as Riemannian Geometry with a pertubation. Furthermore Randers metrics are also obtained as solution to Zermelo’s Navigation Problem. We will also use classification theorems of Randers metrics of constant flag curvature and Einstein Randers metrics in terms of Zermelo’s Navigation Problem. Using Randers metrics we are going to construct a 3-parameter family of Einstein-Finsler metrics with non-constant flag curvature and to get such family we use a Killing vector field and a Riemannian metric which is the Hawking Taub-NUT metric. / Neste trabalho estudaremos a Geometria de Finsler. Em particular, estudaremos a Geometria de Randers que pode ser visto como a mais simples perturbação da Geometria Riemanniana. Além disso, veremos também que métricas de Randers podem ser obtidas como soluções do Problema Navegacional de Zermelo. Utilizaremos também resultados que caracterizam métricas de Randers com curvatura flag constante e métricas de Randers do tipo Einstein em termos do Problema Navegacional de Zermelo. Usando métricas de Randers vamos construir uma família a 3 parâmetros de métricas de Einstein-Finsler com curvatura flag não constante e para obter tal família utilizaremos um campo de Killing e uma métrica Riemanniana que é a métrica de Hawking Taub-NUT.

Cette thèse traite de quelques problèmes classiques en géométrie complexe. La première partie est consacrée à la géométrie Finslérienne complexe. Étant donnés deux fibrés vectoriels holomorphes E1 et E2, munis respectivement de deux structures Finslériennes F1 et F2, on construit une métrique Finslérienne F sur le fibré E 1 ⊗ E 2 faisant intervenir les structures Finslériennes initiales. Moyennant une hypothèse sur les sections globales de E1* et E2*, on donne une condition optimale sous laquelle F est strictement pseudo convexe à courbure négative. Ce résultat est présenté après un chapitre constituant un background Finslérien témoignant de la recherche bibliographique en amont de cette thèse et de quelques initiatives et essais personnels. La seconde partie de ce travail traite d'un problème en géométrie Kählerienne. On prouve l'existence d'une fonction "extrémale" minorant toutes les fonctions admissibles (c'est à dire strictement pseudo convexe à la métrique initiale près) à sup nul sur des variétés de Fano non toriques, à savoir la grassmannienne complexe G m,nm ( C ). Les fonctions considérées sont invariantes par un groupe d'automorphismes convenablement choisi. Cette minoration est faite dans le but de calculer l'invariant de Tian sur de telles variétés, les initiatives dans le cas non torique restant très rares, même sur les variétés les plus simples. / This thesis deals with some classical problems in complex geometry. The first part is devoted to a problem in complex Finsler Geometry. Giving two holomorphic vector bundles E1 and E2, respectively endowed with two Finsler structures F1 and F2, we build a Finsler metric F on E 1 ⊗ E 2 involving the two initial Finsler structures. This is done under some assumptions on global sections of E1* and E2*. We give an optimal condition under which F is strictly pseudo convex with negative curvature. This result is preceded by a chapter containing a background material in complex Finsler geometry and some personal attempts. The second part of this thesis deals with a problem in Kähler Geometry. We prove the existence of an "extremal" function lower bounding all admissible functions (ie plurisubharmonic functions modulo a metric) with sup equal to zero on the complex Grassmann manifold G m,nm ( C ). The functions considered are invariant under a suitable automorphisms group. This gives a conceptually simple method to compute Tian's invariant in the case of a non toric manifold.