Maximum norm error analysis of a nonmatching grids finite element method for linear elliptic PDEs

In this paper, we study a nonmatching grid finite element approximation of linear elliptic PDEs in the context of the Schwarz alternating domain decomposition.We show that the approximation converges optimally in the maximum norm, on each subdomain, making use of the geometrical convergence of both the continuous and corresponding discrete Schwarz sequences. We also give some numerical results to support the theory.