We consider the analysis and numerical solution of a forward-backward boundary value problem. We provide some motivation, prove existence and uniqueness in a function class especially geared to the problem at hand, provide various energy estimates, prove a priori error estimates for the Galerkin method, and show the results of some numerical computations. AMS Subject Classification. 65M60, 65N3...

We study a dynamic model for viscoelastic materials based on a constitutive equation of fractional order. This results in an integrodifferential equation with a weakly singular convolution kernel. We discretize in the spatial variable by a standard Galerkin finite element method. We prove stability and regularity estimates which show how the convolution term introduces dissipation into the equa...

We derive new a-priori and a-posteriori error estimates for mixed nite element discretizations of second-order elliptic problems with general Robin boundary conditions, parameterized by a non-negative and piecewise constant function ε ≥ 0. The estimates are robust over several orders of magnitude of ε, ranging from pure Dirichlet conditions to pure Neumann conditions. A series of numerical expe...

in this article, we study the new streamline diffusion finite element for treating the linear second order hyperbolic initial-boundary value problem. we prove a posteriori $ l^2(l^2)$ and error estimates for this method under minimal regularity hypothesis. test problem of an application of the wave equation in the laser is presented to verify the efficiency and accuracy of the method.

Classically there are two points of view in the study of global existence problems in the theory of functions of a complex variable. One is to piece together local solutions (such as power series), always staying within the category of holomorphic functions. This method seems to have been initiated by Weierstrass; in the theory of several complex variables it has been implemented by the study o...

The reaction-diffusion system of Fitzhugh Nagumo is considered. The initialboundary problems with Neumann and Dirichlet conditions are analyzed. By means of an equivalent semilinear integrodifferential equation which characterizes several dissipative models of viscoelasticity, biology, and superconductivity, some results on existence, uniqueness and a priori estimates are deduced both in the li...

The numerical approximation to a parabolic control problem with control and state constraints is studied in this paper. We use standard piecewise linear and continuous finite elements for the space discretization of the state, while the backward Euler method is used for time discretization. A priori error estimates for control and state are obtained by an improved maximum error estimate for cor...

Standard error estimates for nite element approximations of nonstationary convection-diiusion problems depend reciprocally on the diffusion parameter ". Therefore, the estimates become worthless in the case of strong convection-dominance 0 < " 1. This work provides an "-uniform convergence theory for nite element discretizations of convection-dominated diiusion problems in Eulerian and Lagrangi...

In this paper, we analyze convergence rates of wavelet schemes for time-dependent convection-reaction equations within the framework of the Eulerian–Lagrangian localized adjoint method (ELLAM). Under certain minimal assumptions that guarantee H1-regularity of exact solutions, we show that a generic ELLAM scheme has a convergence rate O(h/ √ Δt +Δt) in L2-norm. Then, applying the theory of opera...