Hamburg, Universiẗat, Diss., 1999. / Dateiformat: zip, Dateien im PDF-Format.

Orientador: Luiz Antonio Barrera San Martin / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Científica / Made available in DSpace on 2018-07-17T08:56:10Z (GMT). No. of bitstreams: 1 Fernandes_MarcoAntonioNogueira_D.pdf: 1422920 bytes, checksum: 9978fd4f47d73ec67f2066dc739bf26a (MD5) Previous issue date: 1992 / Resumo: Não informado. / Abstract: Not informed. / Doutorado / Doutor em Matemática

On considère la structure du Vect(R)-module sur les espaces des opérateurs différentiels bilinéaires agissant sur les espaces de densités. On calcule la première cohomologie différentielle des champs de vecteurs d’algèbre de Lie Vect(R) avec des coefficients dans l’espace des opérateurs différentiels bilinéaires agissant sur les densités pondérées.On considère l’action de Vect(S1) par la dérivée de Lie sur les espaces d’opérateurs pseudodifférentiels DO. On étudie les déformations h-triviales de l’intégration standard de l’algèbre de Lie Vect(S1) de champs de vecteurs lisses sur le cercle, dans l’algèbre de Lie de fonctions sur le fibré cotangent T*S1. On classe les déformations de cette action qui deviennent triviales une fois limitées à h où h = aff(1) ou sl(2). Les conditions nécessaires et suffisantes pour l’intégrabilité des déformations infinitésimales sont données. / We consider the Vect(R)-module structure on the spaces of bilinear differential operators acting on the spaces of weighted densities.We compute the first differential cohomology of the vector fields Lie algebra Vect(R) with coefficients in space of bilinear differential operators acting on weighted densities. we consider the action of Vect(S1) by Lie derivative on the spaces of pseudodifferential operators . We study the h-trivial deformations of the standard embedding of the Lie algebra Vect(S1) of smooth vector fields on the circle, into the Lie algebra of functions on the cotangent bundle T∗S1. We classify the deformations of this action that become trivial once restricted to h, where h = aff(1) or sl(2). Necessary and sufficient conditions for integrability of infinitesimal deformations are given.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Física, Programa de Pós-Graduação em Física, 2016. / Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2016-08-19T17:32:34Z No. of bitstreams: 1 2016_CarlosCésardaSilvaJúnior.pdf: 406403 bytes, checksum: dd360fb49ecc7658d0ec18c72c90019b (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2016-09-05T18:52:40Z (GMT) No. of bitstreams: 1 2016_CarlosCésardaSilvaJúnior.pdf: 406403 bytes, checksum: dd360fb49ecc7658d0ec18c72c90019b (MD5) / Made available in DSpace on 2016-09-05T18:52:40Z (GMT). No. of bitstreams: 1 2016_CarlosCésardaSilvaJúnior.pdf: 406403 bytes, checksum: dd360fb49ecc7658d0ec18c72c90019b (MD5) / Nesta dissertação, são discutidos alguns modelos para encontrar geradores de simetrias de Lie. Essas simetrias são importantes para mapear soluções (embora a princípio esse ponto não seja o foco desse trabalho). Os modelos classícos da simetria de Lie são apresentados, e com eles, modelos para encontrar simetrias de equações íntegro-diferenciais e fracionarias são construídos. Geradores de uma mesma equação são encontrados usando dois modelos diferentes, com o objetivo de demonstrar a equivalência entre esses modelos. _________________________________________________________________________________________________ ABSTRACT / This dissertation will discuss about some methods to find Lie’ssymmetry generators. These symmetries are important to map solutions (although it will not be considered the focus of this work). Classic Lie’ssymmetry methods are presented, and alongside with them, other methods of Integro-differential and fractional equations are built to find symmetries. Generators from the same equation are found by using two different models, aiming to demonstrate equivalence between these methods.

In this work we study the applications of Lie symmetry analysis to certain nonlinear evolution equations of mathematical physics. Exact solutions and conservation laws are obtained for such equations. The equations which are considered in this thesis are a generalized Korteweg-de Vries-Burgers equation, a two-dimensional integrable generalization of the Kaup-Kupershmidt equation, a coupled Korteweg-de Vries system, a generalized coupled variable-coefficient modified Korteweg-de Vries system, a new coupled Korteweg-de Vries system and a new coupled Kadomtsev-Petviashvili system. The generalized Korteweg-de Vries-Burgers equation is investigated from the point of view of Lie group classification. We show that this equation admits a four-dimensional equivalence Lie algebra. It is also shown that the principal Lie algebra consists of a single translation symmetry. Several possible extensions of the principal Lie algebra are computed and their associated symmetry reductions and exact solutions are obtained. The Lie symmetry method is performed on a two-dimensional integrable generalization of the Kaup-Kupershmidt equation. Exact solutions are obtained using the Lie symmetry method in conjunction with the extended tanh method and the extended Jacobi elliptic function method. In addition to exact solutions we also present conservation laws which are derived using the multiplier approach. A coupled Korteweg-de Vries system and a generalized coupled variable-coefficient modified Korteweg-de Vries system are investigated using Lie symmetry analysis. The similarity reductions and exact solutions with the aid of simplest equations and Jacobi elliptic function methods are obtained for the coupled Korteweg-de Vries system and the generalized coupled variable-coefficient modified Korteweg-de Vries system. In addition to this, the conservation laws for the two systems are derived using the multiplier approach and the conservation theorem due to Ibragimov. Finally, a new coupled Korteweg-de Vries system and a new coupled Kadomtsev Petviashvili system are analyzed using Lie symmetry method. Exact solutions are obtained using the Lie symmetry method in conjunction with the simplest equation, Jacobi elliptic function and (G'/G)-expansion methods. Conservation laws are also obtained for both the systems by employing the multiplier approach. / Thesis (PhD.(Applied Mathematics) North-West University, Mafikeng Campus, 2013

En este trabajo estudiamos el álgebra de Lie asociado con la filtración de la serie central del grupo de trenzas pura de Artin y probamos que es una extensión de las álgebras de Lie libres.

Thesis (Ph.D.)--University of Toledo, 2006. / Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Mathematics." Bibliography: leaves 79-82.

No description available.

1 v. (various paging) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1980) from the Dept. of Mathematical Physics, University of Adelaide

Thesis (Ph.D. 1980) from the Department of Mathematical Physics, University of Adelaide.