A priori and a posteriori error analysis for a system of singularly perturbed Volterra integro-differential equations

Abstract

In this work, we consider a system of Volterra integro-differential equations with initial conditions. The derivative term in equations is multiplied with distinct small positive parameters giving rise to overlapping layers. We propose a numerical scheme that avoids the extra condition on the problem’s data required by the scheme of Liang et al. (Comput Appl Math 39:255, 2020). We derive a priori and a posteriori error bounds for the proposed scheme and further rectify the shortcomings of a posteriori error estimation in Liang et al. (Comput Appl Math 39:255, 2020). Numerical results are presented in the form of graphs and tables that validate the proposed theory. © 2023, The Author(s) under exclusive licence to Sociedade Brasileira de Matemática Aplicada e Computacional.