tin the appendix to this chapter, the linear programming formulations are given for activity time-cost trade-off curves that are either continuous, or a collection of feasible time-cost points. These formulations can be extended to cover the case where combinations of these two types of trade-off functions occur. An analysis of this problem indicates that the transitions can occur in three distinct ways as shown in Figure 9-12, i.e., any combinations of continuous curves and discrete points can be handled by appropriate combinations of these three transitions. Write out the linear programming formulation for each of these transitions.