ADAPTIVE H- AND H-R METHODS FOR SYMMS INTEGRAL-EQUATION

In this paper we present the adaptive h-, r- and h-r methods for the G alerkin approximation of Symm's integral equation. The a posteriori er ror estimate depends on a localized a priori error estimate and local finite differences of the computed solution. The optimal mesh for thes e three methods is obtained by using a mesh grading function. The nume rical results for a polygonal problem, and a comparison between our er ror estimate and the residual error estimate, are also presented. More over, we briefly describe how to apply our method to a two-dimensional elasticity problem. (C) 1998 Elsevier Science S.A. All rights reserve d.