On graded meshes for a two-parameter singularly perturbed problem

A one-dimensional reaction–diffusion–convection problem is numerically solved by a finite element method on two layer-adapted meshes, Duran-type mesh and Duran–Shishkin-type mesh, both defined by recursive formulae. Robust error estimates in the energy norm are proved. Numerical results are given to illustrate the parameter–uniform convergence of numerical approximations.