A POSTERIORI ERROR ESTIMATES IN ADINI FINITE ELEMENT FOR EIGENVALUE PROBLEMS

In this paper, we discuss a posteriori error estimates of the eigenvalue $lambda_h$ given by Adini nonconforming finite element. We give an asymptotically exact error estimator of the $lambda_h$. We prove that the order of convergence of the $lambda_h$ is just 2 and the $lambda_h$ converge from below for sufficiently small $h$.