Residual type a posteriori error estimates for elliptic obstacle problems
First residual-type a posteriori error estimators for piecewise linear finite element approximations to the simplest elliptic obstacle problem \[ u\in K: (\nabla u,\nabla(v- u))\geq (f,v- u)\;\forall v\in K \] are derived. Both upper and lower bounds are proved and their optimality is explored with several examples. Sharp a priori bounds for the a posteriori estimators are given. No numerical tests are presented.
scientific article; zbMATH DE number 1423200
scientific article