Before revision:  In particular, by tracking the evolution of subspace angles between eigenvectors of successive eigenproblems, it was shown that these angles decrease noticeably after the first few iterations and become close to collinear : the closer to convergence the stronger the correlation becomes .
After revision:  In particular, by monitoring the subspace angles between eigenvectors of successive eigenproblems, it was shown that these angles decrease noticeably after the first few iterations and become close to collinear : the closer to convergence the stronger the correlation becomes .