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Mostrando ítems 1-10 de 38
Artículo
Quasi-similarity of contractions having 2 x 2 a singular characteristic function
(Elsevier, 2008)
LetT1:H1→H1be a completely non-unitary contraction having a 2×2 singular characteristic function Θ1; thatis, Θ1=[θi,j]i, j=1,2withθij∈H∞and det(Θ1)=0. Asit is well known, Θ1is a singular matrix if and only ifΘ1can be written ...
Artículo
Artículo
Bifurcation behavior of a superlattice model
(Society for Industrial and Applied Mathematics, 2006)
We present a complete description of the stationary and dynamical behavior of semiconductor superlattices in the framework of a discrete drift model by means of numerical continuation, singular perturbation analysis, and ...
Artículo
The Postprocessed Mixed Finite-Element Method for the Navier–Stokes Equations: Refined Error Bounds
(Society for Industrial and Applied Mathematics, 2007)
A postprocessing technique for mixed finite-element methods for the incompressible Navier–Stokes equations is analyzed. The postprocess, which amounts to solving a (linear) Stokes problem, is shown to increase the order ...
Artículo
On Pták's generalization of Hankel operators
(Springer, 2001)
In 1997 Pták defined generalized Hankel operators as follows: Given two contractions T1 ∈ B(H1) and T2 ∈ B(H2), an operator X: H1 → H2 is said to be a generalized Hankel operator if T2X = XT ∗ 1 and X satisfies a ...
Artículo
Postprocessing finite-element methods for the Navier–Stokes Equations: the Fully discrete case
(Society for Industrial and Applied Mathematics, 2008)
An accuracy-enhancing postprocessing technique for finite-element discretizations of the Navier–Stokes equations is analyzed. The technique had been previously analyzed only for semidiscretizations, and fully discrete ...
Artículo
Analysis of an age-structured predator-prey model with disease in the prey
(Elsevier, 2006-09)
We study a nonlinear predator-prey model in which the prey population is affected by a mild disease, but has an effect on the death-rate and is assumed to have age structure. We assume that the predator population grows ...
Artículo
Existence of a Reversible T-Point Heteroclinic Cycle in a Piecewise Linear Version of the Michelson System
(Society for Industrial and Applied Mathematics, 2008)
The proof of the existence of a global connection in differential systems is generally a difficult task. Some authors use numerical techniques to show this existence, even in the case of continuous piecewise linear systems. ...
Artículo
Bifurcación Silla-Nodo de Conos Invariantes en sistemas lineales a trozos Vía Bifurcación Foco-Centro-Ciclo Límite
(Sema, 2008)
En este trabajo se considera la existencia de conos invariantes en sistemas dinámicos continuos tridimensionales lineales a trozos, dada la relevancia que estas variedades invariantes tienen en la determinación de la ...
Artículo
Fixed points and boundary behaviour of the Koenigs function
(2004)
We analyze the relationship between the fixed points of different iterates of an analytic self-map of the unit disk. We show that, in general, a boundary fixed point of such a function is not a fixed point of its iterates. ...