The finite element approximation of optimal control problems for semilinear elliptic partial differential equation is considered, where the control belongs to a finite-dimensional set and state constraints are given in finitely many points of the domain. Under the standard linear independency condition on the active gradients and a strong second-order sufficient optimality condition, optimal er...

Atmospheric tomography is a prerequisite step before wavefront perturbations can be corrected in Multi Conjucate Adaptive Optics (MCAO) systems. Recently, the use of a Landweber-Kaczmarz iteration has been proposed to solve the tomography problem. However, due to the geometric partitioning of the update steps in this method, discontinuities in the solution appear that are physically implausible...

In the first part of this chapter we focus on the question of well-posedness of boundary-value problems for linear partial differential equations of elliptic type. The second part is devoted to the construction and the error analysis of finite difference schemes for these problems. It will be assumed throughout that the coefficients in the equation, the boundary data and the resulting solution ...

In this paper, we use the BiCG, BiCGSTAB methods as preconditioned techniques. Also we compare the preconditioned Krylov subspace methods such as GMRES, GMRES(m), QMR, BiCG, CGS, BiCGSTAB for solving linear systems arising from a class of fourth-order approximations for solving the elliptic partial differential equation Auxx + Buyy = f(x,y,u,ux,uy), where A and B are constants. Numerical result...

We study a spatially semidiscrete and a completely discrete finite element model for a nonlinear system consisting of an elliptic and a parabolic partial differential equation describing the electric heating of a conducting body. We prove error bounds of optimal order under minimal regularity assumptions when the number of spatial variables d < 3. We establish the existence of solutions with th...

Abstract. In this paper we consider the linear second order partial differential equation with non-constant coefficients; then by using the double convolution product we produce new equations with polynomials coefficients and we classify the new equations. It is shown that the classifications of hyperbolic and elliptic new equations are similar to the original equations that is the classificati...

Over the last two decades, classical Schwarz methods have been extended to systems of hyperbolic partial differential equations, using characteristic transmission conditions, and it has been observed that the classical Schwarz method can be convergent even without overlap in certain cases. This is in strong contrast to the behavior of classical Schwarz methods applied to elliptic problems, for ...