Hakki Duru

A uniformly convergent finite difference method for a singularly perturbed initial value problem

Initial value problem for linear second order ordinary differential equation with small parameter by the first and second derivatives is considered. An exponentially fitted difference scheme with constant fitting factors is developed in a uniform mesh, which gives first-order uniform convergence in the sense of discrete maximum norm. Numerical results are also presented.

A uniformly convergent difference method for the periodical boundary value problem

Abstract The periodical boundary value problem for linear second-order ordinary differential equation with small parameter by the first and second derivatives is considered. By the method of integral identities with the use of exponential basis functions and interpolating quadrature rules with weight and remainder term in integral form, an exponentially fitted difference scheme is constructed in a uniform mesh which gives first-order uniform convergence in the discrete maximum norm. Numerical experiments support these theoretical results.

Uniform difference method for a parameterized singular perturbation problem

We consider a uniform finite difference method on a B-mesh is applied to solve a singularly perturbed quasilinear boundary value problem (BVP) depending on a parameter. We give a uniform first-order error estimates in a discrete maximum norm. Numerical results are presented that demonstrate the sharpness of our theoretical analysis.

A parameter-uniform numerical method for a Sobolev problem with initial layer

The present study is concerned with the numerical solution, using finite difference method of a one-dimensional initial-boundary value problem for a linear Sobolev or pseudo-parabolic equation with initial jump. In order to obtain an efficient method, to provide good approximations with independence of the perturbation parameter, we have developed a numerical method which combines a finite difference spatial discretization on uniform mesh and the implicit rule on Shishkin mesh(S-mesh) for the time variable. The fully discrete scheme is shown to be convergent of order two in space and of order one expect for a logarithmic factor in time, uniformly in the singular perturbation parameter. Some numerical results confirming the expected behavior of the method are shown.

Finite-difference method for parameterized singularly perturbed problem

We study uniform finite-difference method for solving first-order singularly perturbed boundary value problem (BVP) depending on a parameter. Uniform error estimates in the discrete maximum norm are obtained for the numerical solution. Numerical results support the theoretical analysis.

Difference schemes for the singularly perturbed Sobolev periodic boundary problem

A finite-difference method is suggested and analyzed for evolution equations of Sobolev type in a single space variable and with boundary layers. The convergence and error estimates for an exponentially fitted difference scheme in an equidistant mesh are obtained. The numerical methods discussed here are extremely robust, in the sense that they have good convergence properties not only for small values of the perturbation parameter, but also for moderate and large values.

Some specialties of the solutions of the differential equations in Banach space

In this paper we investigate the existence and uniqueness of solution of differential equation in Banach space under condition (1.2). The theorems which we proved had been investigated at first in the papers [Canada, Math. Bull. 2(1) (1959); Canada, Math. Bull. 1(1) (1958); Y.D. Mamedov, The Convergence of Iterations for Differential Equations in Banach Spaces, in: Convergent Methods of Ordinary Differential Equations, Naukova Dumka, Kiev, 1964 (Russian)] by other methods for special case.

On continuity properties of potentials depending on λ-distance

This study establishes the theorem on continuity of generalized Riesz potentials with non-isotrop kernels depending on @l-distance.