“…A good example is the set of matrices of some fixed rank: given a singular value decomposition of a matrix, projecting it onto this set is immediate. Furthermore, nonconvex alternating projection algorithms and analogous heuristics are quite popular in practice, in areas such as inverse eigenvalue problems [10,11], pole placement [35,51], information theory [48], low-order control design [23,24,36] and image processing [7,50]. Previous convergence results on nonconvex alternating projection algorithms have been uncommon, and have either focussed on a very special case (see for example [10,30]), or have been much weaker than for the convex case [14,48].…”