Operator Theory
Mostrando 13-24 de 91 artigos, teses e dissertações.
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13. Cálculos de substituições explícitas à La Bruijn com sistemas de tipos com interseção
The ג-calculus is a well known theoretical computation model as old as the concept of computable functions. Due to the substitution definition as a meta-operator there exists a great quantity of variations of this computational system in which the operation of substitution is treated explicitly. In this work we investigate intersection type systems for
Publicado em: 2010
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14. A técnica como dispositivo de controle do corpomídia / Technique as an Instrument of Bodymedia Control
Corporal technique has been defined by Western Common Sense as being a mechanical repetition that disciplines the body with a specific purpose in mind. This thesis proposes to destabilize traditional dichotomies of the theory-practice and mind-body type that have been responsible for the longevity of some ontological metaphors such as the body-recipient and
Publicado em: 2010
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15. ABP estimates and Ambrosetti-Prodi type problems for nonlinear differential operators / Estimativas ABP e problemas do tipo Ambrosetti-Prodi para operadores diferenciais não lineares
The aim of this work is to obtain ABP estimates for fully nonlinear operators and to study problems of the Ambrosetti-Prodi type for the p-Laplacian operator in two cases: superlinear case for the equation and the sublinear case for the system. For this, we use the sub and supersolution method and the Leray Schauder degree theory, to obtain in the two cases,
Publicado em: 2009
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16. Operadores integrais gerados por núcleos em multi-escalas / Integral operators generated by multi-scale kernels
We study Mercer like kernels, a very special class of positive definite kernels possessing the description given by many results labeled as Mercers Theorem. We explore some of their properties which are needed in the development of this work and construct their native space. In the second half of the work, we consider Mercer kernels defined by a multi-scale
Publicado em: 2009
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17. Uma teoria de regularidade para certas equaÃÃes de evoluÃÃo em escala de tempo discreto e contÃnuo
Nesta tese estudamos trÃs tipos de equaÃÃo de evoluÃÃo. Para a equaÃÃo do Oscilador HarmÃnico semilinear discreto desenvolvemos uma teoria de perturbaÃÃo e apresentamos um resultado de estabilidade de sua soluÃÃo. Para isso, utilizamos uma caracterizaÃÃo de regularidade maximal discreta via espaÃos UMD. Estudamos tambÃm a S-assintoticidade
Publicado em: 2009
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18. n-Larguras de conjuntos de funções suaves sobre a esfera S POT. d / n-Widths of sets of smooth functions on the sphere S POT. d
The purpose of this work is to study estimates of n-widths of sets of smooth functions on the d-dimensional real unitary sphere. These sets are generated by multipliers operator. Another aim is to develop a text in portuguese about the most important n-widths, your properties and relations. We do this in the first chapter. In the second chapter, we develop a
Publicado em: 2009
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19. Simulador de meios porosos saturados elastoplasticos / Numerical simulator of saturated elastoplastic porous media
The exploration of mineral resources is growing in importance in the Brazilian economy. Since the environments in which these resources are found are becoming increasingly more complex and challenging for the production phase, currently unavailable knowledge and technologies are required to produce these reserves. In the particular well drilling and completi
Publicado em: 2009
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20. Oscilador de Dirac: ImplicaÃÃes da violaÃÃo da simetria de Lorentz e da massa dependente da posiÃÃo.
In this work we study the Dirac Oscillator (DO) in a threefold way. In the first way, we study DO with Lorentz symmetry violation. This violation is implemented through vectorial and an axial terms. We realize a non-relativistic limit and we obtain that the background vector field does not modify the energy spectrum. However, in the case of the background ax
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/07/2008
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21. Analytical descriptions of DEPT NMR spectroscopy for ISn(I = 1,S = 1; n = 1, 2, 3, 4) spin systems
A DEPT pulse sequence is well-known 13C-detected, edited-pulse and cross polarization transfer NMR experiment which offers to selective detection capability of CH, CH2 and CH3 groups from each other. The product operator theory is widely used for analytical descriptions of the cross polarization transfer NMR experiments for weakly coupled spin systems. In th
Brazilian Journal of Physics. Publicado em: 2008-09
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22. Dirac equation: representation independence and tensor transformation
We define and study the probability current and the Hamiltonian operator for a fully general set of Dirac matrices in a flat spacetime with affine coordinates, by using the Bargmann-Pauli hermitizing matrix. We find that with some weak conditions on the affine coordinates, the current, as well as the spectrum of the Dirac Hamiltonian, thus all of quantum mec
Brazilian Journal of Physics. Publicado em: 2008-06
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23. On the quantum dynamics of non-commutative systems
This is a review paper concerned with the global consistency of the quantum dynamics of non-commutative systems. Our point of departure is the theory of constrained systems, since it provides a unified description of the classical and quantum dynamics for the models under investigation. We then elaborate on recently reported results concerned with the suffic
Brazilian Journal of Physics. Publicado em: 2008-06
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24. Comportamento assintótico para soluções de certas equações diferenciais funcionais periódicas / Asymptotic behavior of solutions to certain periodic functional differential equations
We are interested in the study of the asymptotic behavior of the solutions of a class of linear autonomous Functional Differential Equations (FDE) of neutral type, where the coeficients of the non neutral part are periodic functions with common period w and the time delays are multiples of w. We employ the spectral theory for linear operators applied to the
Publicado em: 2008