The Rate of Convergence for the Method of Alternating Projections, II

The purpose of the paper is threefold: 1. To develop a useful error bound for the method of alternating projections which is relatively easy to compute and remember; 2. To exhibit a counterexample to a conjecture of Kayalar and Weinert; 3. To show that in the case of at least three subspaces. any error bound which only depends on the angles between the various subspaces involved can ne¨er be sharp.