The theory of Jocalization first introduced in topology by D. Sullivan [6] has been exploited by many topologists, e.g. A.K. Bousfield - D.M. Kan [1], P. Hilton G. Mislin J. Roitberg [2], and works particularly well in the homotopy category of nilpotent spaces, i.e. spaces whose Postnikov system admits a principal refinement...
