Convergence of dual finite element approximations for unilateral boundary value problems

summary:A semi-coercive problem with unilateral boundary conditions of the Signoriti type in a convex polygonal domain is solved on the basis of a dual variational approach. Whereas some strong regularity of the solution has been assumed in the previous author's results on error estimates, no assumption of this kind is imposed here and still the $L^2$-convergence is proved