“…Regarding abstract results on the convergence of GF and GD processes we refer, for example, to [5,34,49,50,56] for the case of convex objective functions, we refer, for instance, to [1,3,4,10,21,39,42,43,46,47,51] for convergence results for GF and GD processes under Lojasiewicz type conditions, and we refer, for instance, to [7,27,44,54] and the references mentioned therein for further results without convexity conditions. In general, without global assumptions on the objective function such as convexity, gradient-based methods may converge to non-global local minima or saddle points.…”