“…Portfolio selection problems with cardinality and/or minimum threshold constraints have been studied extensively in recent literature. For exact solution methods, please see, e.g., [7,37,44,13,6,17,29]. For inexact solution methods, such as heuristics, local search methods and randomized techniques, please see, e.g., [34,12,15,35,43,38,16,40,19,46].…”