Convergence Rate and Quasi-Optimal Complexity of Adaptive Finite Element   Computations for Multiple Eigenvalues
  In this paper, we study an adaptive finite element method for multiple eigenvalue problems of a class of second order elliptic equations. By using some eigenspace approximation technology and its crucial property which is also presented in this paper, we extend the results in \cite{dai-xu-zhou08} to multiple eigenvalue problems, we obtain both convergence rate and quasi-optimal complexity of the adaptive finite element eigenvalue approximation. 
Xiaoying Dai, Lianhua He, and Aihui Zhou
math.NA