“…These problems consist of finding one or more trees (or paths) on a given graph satisfying some given constraints while minimizing or maximizing an objective function. Some COT problems have been considered and solved in the literature, e.g., Degree Constrained Minimum Spanning Tree (DCMST) [45,7], Bounded Diameter Minimum Spanning Tree (BDMST) [35], Capacitated Minimum Spanning Tree problem (CMST) [56,3], Minimum Diameter Spanning Tree (MDST) [50], EdgeWeighted k-Cardinality Tree (KCT), [20,25], Steiner Minimal Tree (SMT) [66,28], Optimum Communication Spanning Tree problems (OCST) [32], etc. We also see many COP problems which have been studied and solved in the literature.…”