Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-08-11T13:12:20Z No. of bitstreams: 1 arquivototal.pdf: 1245634 bytes, checksum: e10d5add0ac7fd6fd557ebc178b4b142 (MD5) / Made available in DSpace on 2017-08-11T13:12:20Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1245634 bytes, checksum: e10d5add0ac7fd6fd557ebc178b4b142 (MD5) Previous issue date: 2013-08-15 / Hesse claimed in [9] that an irreducible projective hypersurface in Pn de ned by an equation with vanishing hessian determinant is necessarily a cone. Gordan and Noether proved in [6] that this is true for n 3 and constructed counterexamples for every n 4. Gordan-Noether and Franchetta gave a classi cation of hypersurfaces in P4 with vanishing hessian and which are not cones, see [6] and [3]. Here we give a geometric approach to the classi cation proposed by Gordan-Noether, providing a classi cation of hypersurfaces with zero Hessian in P4, following the lines of Garbagnati-Reppeto in [4]. / Hesse afirmou em [9] que uma hipersuperfície projetiva irredutível em Pn definida por uma equação com hessiano nulo necessariamente é um cone. Gordan e Noether provaram em [6] que isso é verdade para n 3 e exibiram contra-exemplos para cada n 4. Gordan-Noether e Franchetta deram uma classi ca c~ao das hipersuperf cies em P4 com hessiano nulo e que n~ao s~ao cones, ver [6] e [3]. Aqui vamos dar uma abordagem geom etrica a classi ca c~ao das hipersuperf cies com hessiano nulo em P4 proposta por Gordan-Noether, seguindo as linhas de Garbagnati-Reppeto em [4].

Στην παρούσα διδακτορική διατριβή μελετάμε τρία Προβλήματα που αναφέρονται στην Ψευδο-Ευκλείδεια Γεωμετρία. Στα δύο πρώτα Κεφάλαια, Κεφάλαιο 1 και Κεφάλαιο 2 αναφέρουμε γνωστά αποτελέσματα και περιγράφουμε βασικές έννοιες της Ρημάννιας και Ψευδό - Ρημάννιας Γεωμετρίας. Στο Κεφάλαιο 3 μελετάμε επιφάνειες εκ περιστροφής στον τρισδιάστατο Lorentz - Minkowski χώρο ικανοποιώντας δοσμένη γεωμετρική συνθήκη. Στο Κεφάλαιο 4 βρίσκουμε όλες τις κανονικές μορφές του τελεστή σχήματος των τρισδιάστατων υπερεπιφανειών τύπου (-, +, -) του τετρασδιάστατου Ψευδο - Ευκλείδειου χώρου τύπου (-, +, -, +). Τέλος, στο Κεφάλαιο 5 μελετάμε τη σχέση που υπάρχει μεταξύ των διαρμονικών και ελαχιστικών υπερεπιφανειών που αναφέρθηκαν στο Κεφάλαιο 4, χρησιμοποιώντας τον τελεστή σχήματός τους. Ειδικότερα, αποδεικνύουμε ότι κάθε τέτοια διαρμονική υπερεπιφάνεια είναι ελαχιστική. / In the present PH.D. thesis we study three problems referred in the pseudo-Euclidean geometry. In the first two chapters, Chapter 1 and Chapter 2, we review known results and describe the basic notions of the Riemannian and Pseudo-Riemannian geometry. In Chapter 3, we study surfaces of revolution of the three dimensional Lorentz-Minkowski space satisfying given geometric condition. In Chapter 4, we find all the canonical forms of the shape operator of the three dimensional hypersurfaces of signature (-, +, -) of the four dimensional pseudo-Euclidean space of signature (-, +, -, +). Finally, in Chapter 5, we study the relation which exists between the biharmonic and minimal hypersurfaces referred in Chapter 4, by using their shape operator. Precisely, we prove that every such biharmonic hypersurface is minimal.

L'objet d'étude de ce mémoire est la géométrie des courbes holomorphes entières à valeurs dans le complémentaire d'hypersurfaces génériques de l'espace projectif complexe. Les conjectures célèbres de Kobayashi et de Green-Griffiths énoncent que pour de telles hypersurfaces, de grand degré, les images de ces courbes entières doivent satisfaire certaines contraintes algébriques. En adaptant les techniques de jets développées notamment par Bloch, Green-Griffiths, Demailly, Siu, Diverio-Merker-Rousseau, pour les courbes à valeurs dans une hypersurface projective (cas dit compact), nous obtenons la dégénérescence algébrique des courbes entières f : ℂ→Pⁿ∖Xd (cas dit logarithmique), pour les hypersurfaces génériques Xd de Pⁿ de degré d ≥ (5n)² nⁿ. Comme dans le cas compact, notre preuve repose essentiellement sur l'élimination algébrique de toutes les dérivées dans des équations différentielles qui sont vérifiées par toute courbe entière non constante. L'existence de telles équations différentielles est obtenue grâce aux inégalités de Morse holomorphes et à une variante simplifiée d'une formule de résidus originalement élaborée par Bérczi à partir de la formule de localisation équivariante d'Atiyah-Bott. La borne effective d ≥ (5n)² nⁿ est obtenue par réduction radicale d'un calcul de résidus itérés de très grande ampleur. Ensuite, la déformation de ces équations différentielles par dérivation le long de champs de vecteurs obliques, dont l'existence est ici généralisée et clarifiée, nous permet d'engendrer suffisamment de nouvelles équations pour réaliser l'élimination algébrique finale évoquée ci-dessus. / The topic of this memoir is the geometry of holomorphic entire curves with values in the complement of generic hypersurfaces of the complex projective space. The well-known conjectures of Kobayashi and of Green-Griffiths assert that for such hypersurfaces, having large degree, the images of these curves shall fulfill algebraic constraints. By adapting the jet techniques developed notably by Bloch, Green-Griffiths, Demailly, Siu, Diverio-Merker-Rousseau, in the case of curves with values in projective hypersurfaces (so-called compact case), we obtain the algebraic degeneracy of entire curves f : ℂ→Pⁿ∖Xd (so called logarithmic case), for generic hypersurfaces Xd in Pⁿ of degree d ≥ (5n)² nⁿ. As in the compact case, our proof essentially relies on the algebraic elimination of all derivatives in differential equations that are satisfied by every nonconstant entire curve. The existence of such differential equations is obtained thanks to the holomorphic Morse inequalities and a simplified variant of a residue formula firstly developed by Bérczi from the Atiyah-Bott equivariant localization formula. The effective lower bound d ≥ (5n)² nⁿ is obtained by radically simplifying a huge iterated residue computation. Next, the deformation of these differential equations by derivation along slanted vector fields, the existence of which is here generalized and clarified, allows us to generate sufficiently many new differential equations in order to realize the final algebraic elimination mentioned above.

In this work, Schr&ouml / dinger and Dirac equations will be examined in geometries that confine the particles to hypersurfaces. For this purpose, two methods will be considered. The first method is the thin layer method which relies on explicit use of geometrical relations and the squeezing of a certain coordinate of space (or spacetime). The second is Dirac&rsquo / s quantization procedure involving the modification of canonical quantization making use of the geometrical constraints. For the Dirac equation, only the first method will be considered. Lastly, the results of the two methods will be compared and some notes on the differences between the results will be included.

In this work, two particular orthogonal and conformal decompositions of the 3+1 dimensional Einstein equation and Arnowitt-Deser-Misner (ADM) formalism for general relativity are obtained. In order to do these, the 3+1 foliation of the four-dimensional spacetime, the fundamental conformal transformations and the Hamiltonian form of general relativity that leads to the ADM formalism, de

PEREIRA, José Ilhano da Silva. Hipersuperfícies mínimas de R4 com curvatura de Gauss-Kronecker nula. 2017. 44 f. Dissertação (Mestrado em Matemática) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Andrea Dantas (pgmat@mat.ufc.br) on 2017-10-02T15:01:31Z No. of bitstreams: 1 2017_dis_jispereira.pdf: 596580 bytes, checksum: 3c2c1a16d4ce273bfb7c246f7926c01a (MD5) / Rejected by Rocilda Sales (rocilda@ufc.br), reason: Boa tarde, Estou devolvendo a Dissertação de JOSÉ ILHANO DA SILVA PEREIRA, pois há alguns erros a serem corrigidos. Os mesmos seguem listados a seguir. 1- FOLHA DE APROVAÇÃO (substitua a folha de aprovação, por outra que não contenha as assinaturas dos membros da banca examinadora) 2- NUMERAÇÃO INDEVIDA (a numeração indevida de página que aparece na folha de aprovação deve ser retirada) 3- RESUMO (retire o recuo de parágrafo presente no resumo e no abstract) 4- PALAVRAS-CHAVE (apenas o primeiro elemento de cada palavra-chave deve começar com letra maiúscula, assim reescreva as palavras-chave como no exemplo a seguir: Hipersuperfícies mínimas) 5- SUMÁRIO (Os títulos dos capítulos principais, que aparecem no sumário e no interior do trabalho, devem estar em caixa alta (letra maiúscula). Ex.: 2 PRELIMINARES 2.1 Tensores 6 – REFERÊNCIAS (retire o conjunto de “citações” à autores que aparece no final das referências bibliográficas, pois elas fogem ao padrão ABNT para a página das referências) Atenciosamente, on 2017-10-04T17:50:58Z (GMT) / Submitted by Andrea Dantas (pgmat@mat.ufc.br) on 2017-10-23T19:57:28Z No. of bitstreams: 1 2017_dis_jispereira.pdf: 333124 bytes, checksum: 37989a2f3787d5914a0c0553afd4e89f (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2017-11-01T12:35:13Z (GMT) No. of bitstreams: 1 2017_dis_jispereira.pdf: 333124 bytes, checksum: 37989a2f3787d5914a0c0553afd4e89f (MD5) / Made available in DSpace on 2017-11-01T12:35:13Z (GMT). No. of bitstreams: 1 2017_dis_jispereira.pdf: 333124 bytes, checksum: 37989a2f3787d5914a0c0553afd4e89f (MD5) Previous issue date: 2017-08-25 / This work does study the complete minimal hypersurfaces in the Euclidean space R4 , with Gauss-Kronecker curvature identically zero. Our main result is to prove that if f: M3 → R4 is a complete minimal hypersurface with Gauss-Kronecker curvature identically zero, nowhere vanishing second fundamental form and scalar curvature boun-ded from below, then f(M3) splits as a Euclidean product L2 × R , where L2 is a complete minimal surface in R3 with Gaussian curvature bounded from below. Moreover, we show a result about the Gauss-Kronecker curvature of f, without any assumption on the scalar curvature. / Este trabalho tem como objetivo estudar as hipersuperfícies mínimas em R4, com curvatura de Gauss-Kronecker identicamente zero. Como resultado principal provamos que se f : M3 → R4 é uma hipersuperfície mínima com curvatura de Gauss-Kronecker identicamente zero, segunda forma fundamental não se anulando em nenhum ponto e curvatura escalar limitada inferiormente, então f(M3) se decompõe como um produto euclidiano do tipo L2 × R , onde L2 é uma superfície mínima de R3 com curvatura Gaussiana limitada inferiormente. Finalmente, apresentamos um resultado sobre a curvatura de Gauss-Kronecker de f sem nenhuma hipótese sobre a curvatura escalar.

Made available in DSpace on 2015-05-15T11:46:26Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 980914 bytes, checksum: a5914e595687839b602a1d3280515022 (MD5) Previous issue date: 2011-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Hesse said in one of his articles that a hypersurface in the projective space Pn that has null hessian polynomial is a cone. Later, Gordam and Noether prove that the statement of Hesse is valid only for n 3, presenting counter-examples for n 4. Initially we tried to solve the problem in a direct and elementary form, been well succeeding only in the case of P1, so we set out to study the dual of variety and polar map associated to the hypersurface X = Z(F) Pn. Having mind that X IF , where IF is the polar map image, and that X is a cone if and only if, X is degenerate. Which brings us to display a series of technical results in order to conclude that IF is a linear variety, speci cally a line if n = 2 and a plane or line if n = 3. Thus we prove for a given hypersurface X = Z(F) Pn. If n 3, then X is a Cone () det [Hess (F)] = 0. / Hesse a rmou em um dos seus artigos que uma hipersuperfície no espaço projetivo Pn que tenha o hessiano polinomial nulo é um cone. Mais tarde, Gordam e Noether provam que a a rmação de Hesse é valida apenas para n 3, apresentando contra- exemplos para n 4. Inicialmente tentamos resolver o problema de maneira direta e elementar, tendo sucesso só no caso de P1, então partimos para o estudo de dual de uma variedade e de mapa polar associado a uma hipersuperfície X = Z(F) Pn. Tendo em consideração que X IF , onde IF é a imagem do mapa polar, e que X é um Cone se, e somente se, X é degenerado. Somos levados a mostrar uma série de resultados técnicos a m de concluir que IF é uma variedade linear, especi camente uma reta se n = 2 e um plano ou uma reta se n = 3. Provando assim que dada uma hipersuperfície X = Z(F) Pn. Se n 3, então X é um cone () det [Hess (F)] = 0.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18766号 / 理博第4024号 / 新制||理||1580(附属図書館) / 31717 / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)准教授 伊藤 哲史, 教授 上田 哲生, 教授 雪江 明彦 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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L’objectif à moyen terme de ce travail est d’explorer quelques formulations des problèmes d’identification de forme et de reconnaissance de surface à partir de mesures ponctuelles. Ces problèmes ont plusieurs applications importantes dans les domaines de l’imagerie médicale, de la biométrie, de la sécurité des accès automatiques et dans l’identification de structures cohérentes lagrangiennes en mécanique des fluides. Par exemple, le problème d’identification des différentes caractéristiques de la main droite ou du visage d’une population à l’autre ou le suivi d’une chirurgie à partir des données générées par un numériseur. L’objectif de ce mémoire est de préparer le terrain en passant en revue les différents outils mathématiques disponibles pour appréhender la géométrie comme variable d’optimisation ou d’identification. Pour l’identification des surfaces, on explore l’utilisation de fonctions distance ou distance orientée, et d’ensembles de niveau comme chez S. Osher et R. Fedkiw ; pour la comparaison de surfaces, on présente les constructions des métriques de Courant par A. M. Micheletti en 1972 et le point de vue de R. Azencott et A. Trouvé en 1995 qui consistent à générer des déformations d’une surface de référence via une famille de difféomorphismes. L’accent est mis sur les fondations mathématiques sous-jacentes que l’on a essayé de clarifier lorsque nécessaire, et, le cas échéant, sur l’exploration d’autres avenues. / The mid-term objective of this work is to explore some formulations of shape identification and surface recognition problems from point measurements. Those problems have important applications in medical imaging, biometrics, security of the automatic access, and in the identification of Lagrangian Coherent Structures in Fluid Mechanics. For instance, the problem of identifying the different characteristics of the right hand or the face from a population to another or the follow-up after surgery from data generated by a scanner. The objective of this mémoire is to prepare the ground by reviewing the different mathematical tools available to apprehend the geometry as an identification or optimization variable. For surface identification it explores the use of distance functions, oriented distance functions, and level sets as in S. Osher and R. Fedkiw ; for surface recognition it emphasizes the construction of Courant metrics by A. M. Micheletti in 1972 and the point of view of R. Azencott and A. Trouvé in 1995 which consists in generating deformations of a reference surface via a family of diffeomorphisms. The accent will be put on the underlying mathematical foundations that it will attempt to clarify as necessary, and, if need be, on exploring new avenues.