dummy activities

The basic network is a combination of events, activities and dummy activities, as illustrated in Figure 29.1.

Dummy activities are actions which do not incur time, but need to be shown to ensure the logic of the network.

Note the introduction of node 9 and dummy activities 11, 12 and 13 to correctly represent the problem as described in the question.

Networks are composed of three main elements: Events, Activities, and Dummy activities.

NOTE that 2 dummy activities were introduced.

Note the introduction of node 8 and the two dummy activities 11 and 12 to correctly represent the condition that activity five cannot start until 3 weeks after the end of activity one.