completion time for all nodes in the graph if eci is the earliest completion time for node ithen the applicable rules are ec ecw max (ecv cv, ( , ) figure shows the earliest completion time for each event in our example event-node graph we can also compute the latest timelci that each event can finish without affecting the final completion time the formulas to do this are lcn ecn lcv min (lcw cv, ( , ) these values can be computed in linear time by maintainingfor each vertexa list of all adjacent and preceding vertices the earliest completion times are computed for vertices by their topological orderand the latest completion times are computed by reverse topological order the latest completion times are shown in figure the slack time for each edge in the event-node graph represents the amount of time that the completion of the corresponding activity can be delayed without delaying the overall completion it is easy to see that slack( ,wlcw ecv cv, / / / / / / / / / figure earliest completion times / / / / / figure latest completion times / / / /