An Optimal Adaptive Finite Element Method for an Obstacle Problem

作者:Carstensen, Carsten*; Hu, Jun
来源:Computational Methods in Applied Mathematics, 2015, 15(3): 259-277.
DOI:10.1515/cmam-2015-0017

摘要

This paper provides a refined a posteriori error control for the obstacle problem with an affine obstacle which allows for a proof of optimal complexity of an adaptive algorithm. This is the first adaptive mesh-refining finite element method known to be of optimal complexity for some variational inequality. The result holds for first-order conforming finite element methods in any spacial dimension based on shape-regular triangulation into simplices for an affine obstacle. The key contribution is the discrete reliability of the a posteriori error estimator from [6] in an edge-oriented modification which circumvents the difficulties caused by the non-existence of a positive second-order approximation [18].