Calcolo, cilt.59, sa.1, 2022 (SCI-Expanded, Scopus)
In this paper, superconvergence approximations of the modified weak Galerkin finite element method for the singularly perturbed two-point elliptic boundary-value problem have been studied. On the piecewise uniform Shishkin mesh, we have established the superconvergence error bounds of O(N-1lnN)k+1 in the discrete energy norm, where k is the degree of polynomials used in the finite element space and N is the number of elements. Stability analyses have been carried out for both singularly perturbed reaction–diffusion and convection-dominated problems. Some numerical examples are presented to support the theoretical findings. Moreover, the numerical experiments show that the proposed method has the superconvergence error bounds of O(N-1lnN)2k in the discrete L∞-norm.