A priori and a posteriori error estimation for singularly perturbed delay integro-differential equations

This article deals with the numerical analysis of a class of singularly perturbed delay Volterra integro-differential equations exhibiting multiple boundary layers. The discretization of the considered problem is done using an implicit difference scheme for the differential term and a composite numerical integration rule for the integral term. The analysis of the discrete scheme consists of two parts. First, we establish an a priori error estimate that is used to prove robust convergence of the discrete scheme on Shishkin and Bakhvalov type meshes. Next, we establish the maximum norm a posteriori error estimate that involves difference derivatives of the approximate solution. The derived a posteriori error estimate gives the computable and guaranteed upper bound on the error. Numerical experiments confirm the theory.

Automated summary

This article presents a numerical analysis of a class of singularly perturbed delay Volterra integro-differential equations with multiple boundary layers. The problem is discretized using an implicit difference scheme for the differential term and a composite numerical integration rule for the integral term. The analysis of the discrete scheme consists of two parts: an a priori error estimate for robust convergence on specific meshes, and a maximum norm a posteriori error estimate involving difference derivatives of the approximate solution. Numerical experiments confirm the theoretical findings.