Differential Algebra
Mostrando 13-23 de 23 artigos, teses e dissertações.
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13. Sobre a existencia de bases SAGBI finitas para o nucleo de k-derivações em k[x1,...,xn] / About the existence of finite SAGBI bases for the kernel of a k-derivation in k[x1,...,xn]
The general objective of this work is to understand the SAGBI bases theory from a structural point of view, seeking criterias for its existence and results that prove its effitiency in the study of certain subalgebras of k[x], as well as to study the general theory of derivations over polynomial rings, its localizations and quotients, in order to explo
Publicado em: 2008
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14. Dynamic simulation of flash drums using rigorous physical property calculations
The dynamics of flash drums is simulated using a formulation adequate for phase modeling with equations of state (EOS). The energy and mass balances are written as differential equations for the internal energy and the number of moles of each species. The algebraic equations of the model, solved at each time step, are those of a flash with specified internal
Brazilian Journal of Chemical Engineering. Publicado em: 2007-06
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15. Matrix differential equations and inverse preconditioners
In this article, we propose to model the inverse of a given matrix as the state of a proper first order matrix differential equation. The inverse can correspond to a finite value of the independent variable or can be reached as a steady state. In both cases we derive corresponding dynamical systems and establish stability and convergence results. The applica
Computational & Applied Mathematics. Publicado em: 2007
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16. Superficies minimas no grupo de Heisengerg / Minimal surfaces on Heisengerg groups
o objetivo deste trabalho é o estudo dos gráficos mínimos no grupo de Heisenberg de dimensão três. Primeiramente fizemos uma descrição deste grupo como grupo de Lie e sua álgebra de Lie. Verificamos que a aplicação exponencial é um difeomorfismo global entre a álgebra de Lie e o grupo de Heisenberg. Seguindo o ciclo natural, passamos a estudar a
Publicado em: 2007
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17. Conhecimentos Mobilizados por alunos sobre a Noção Integral no contexto das Concepções Operacionais e Estruturais
The aim of this research was to investigate the knowledge mobilized by those students who have studied Integral, a subject that permeates a major part of the Integral and Differential Calculus (IDC) course and is a source of difficulties for the students. The goal was to analyze the explicit knowledge of those who have studied this concept in a regular IDC c
Publicado em: 2007
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18. Teoria dos mÃdulos idealizadores diferenciais
Given an ideal in a polynomial ring (with coefficients in a field usually assumed to have characteristic zero), we may consider the derivations that preserve it. They give rise to a special module called differential idealizer (of the given ideal). Such an object plays a primordial role in this thesis, which is divided into two main sections. In the first se
Publicado em: 2006
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19. INVARIANT DIFFERENTIAL OPERATORS ON A SEMISIMPLE LIE ALGEBRA
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20. A brief survey of symmetry in mathematics
This paper presents a brief survey of the idea of symmetry in mathematics, as exemplified by some particular developments in algebra, differential equations, topology, and number theory.
The National Academy of Sciences of the USA.
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21. A new family of algebras underlying the Rogers-Ramanujan identities and generalizations
The classical Rogers-Ramanujan identities have been interpreted by Lepowsky-Milne and the present authors in terms of the representation theory of the Euclidean Kac-Moody Lie algebra A1(1). Also, the present authors have introduced certain “vertex” differential operators providing a construction of A1(1) on its basic module, and Kac, Kazhdan, and we have
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22. A new class of counterexamples to the integrability problem
For many years, it was believed that the solvability of the integrability problem for a transitive Lie pseudogroup depends only on the local solvability of linear differential operators arising from the abelian quotients in Guillemin's Jordan-Hölder decomposition for the transitive Lie algebra associated to the pseudogroup. We provide an example of a transi
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23. The Rogers-Ramanujan identities: Lie theoretic interpretation and proof
The two Rogers-Ramanujan identities, which equate certain infinite products with infinite sums, are among the most intriguing of the classical formal power series identitites. It has been found by Lepowsky and Milne that the product side of each of them differs by a certain factor from the principally specialized character of a certain standard module for th