Riemann Hilbert
Mostrando 1-7 de 7 artigos, teses e dissertações.
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1. O Décimo problema de Hilbert
Neste trabalho apresentamos uma demonstração da insolubilidade do Décimo Problema de Hilbert, que investiga a existência de um método para determinar se dada uma equação Diofantina qualquer podemos determinar se esta tem ou não uma solução. Começamos desenvolvendo alguns tópicos de teoria de números, que serão úteis em vários momentos, nesta
Publicado em: 2010
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2. Simulação da injeção de bancos de agua com polimeros na recuperação de petroleo
In this presentation we work on the problem of the injection of water banks with polymers in enhanced oil recovery. The mathematical model consists of a system of conservation laws with appropriate initial conditions and of boundaries. We have used the solutions of the Riemann problem ( [ISA] and [JOH] ) associated to this system to propose an algorithm whic
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/12/1999
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3. Leques de viscosidade e delta-choques em problemas Reimann
Neste trabalho consideramos um problema de Riemann 2 x 2 estritamente hiperbólico cujas curvas de Hugoniot por determinados estados à esquerda (ul , vl) apresentam assÍntotas verticais. Este fato permite a existência de regiões do plano de fase constituídas de estados à direita (ur, vr) que não podem ser conectados a (ul , vl) por ondas clássicas. P
Publicado em: 1996
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4. An extension of the steepest descent method for Riemann-Hilbert problems: The small dispersion limit of the Korteweg-de Vries (KdV) equation
This paper extends the steepest descent method for Riemann-Hilbert problems introduced by Deift and Zhou in a critical new way. We present, in particular, an algorithm, to obtain the support of the Riemann-Hilbert problem for leading asymptotics. Applying this extended method to small dispersion KdV (Korteweg-de Vries) equation, we (i) recover the varia
The National Academy of Sciences.
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5. Hilbert Transforms in Yukawan Potential Theory
If H denotes the classical Hilbert transform and Hu(x) = v(x), then the functions u(x) and v(x) are the values on the real axis of a pair of conjugate functions, harmonic in the upper half-plane. This note gives a generalization of the above concepts in which the Laplace equation Δu = 0 is replaced by the Yukawa equation Δu = μ2u and in which the Cauchy-R
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6. The curvature of a Hilbert module over ℂ[z1, … , zd]
A notion of curvature is introduced in multivariable operator theory. The curvature invariant of a Hilbert module over ℂ[z1, … , zd] is a nonnegative real number which has significant extremal properties, which tends to be an integer, and which is hard to compute directly. It is shown that for graded Hilbert modules, the curvature agrees with the E
The National Academy of Sciences.
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7. The Spectrum of Seminormal Operators
With every pair of bounded self-adjoint operators {U,V} on Hilbert space such that VU - UV = (1/πi)C, where C is trace class, there is associated a certain function of two complex variables called the determining function of the pair. It was previously shown how the determining function can be obtained as the solution of a certain Riemann-Hilbert problem ca