Activities and Precedence - Scheduling & the Critical Path

Critical path scheduling starts with an acyclic activity network. Durations and precedence arcs are pinned, then every schedule value is recomputed from that DAG. The lesson reads the project as dependency evidence: which work can begin immediately, which work branches, and which work must wait at a merge.

highlighted = computed this step

Activities

The project has 6 activities. Each activity is work with a fixed duration and a named position in the precedence graph. Why: CPM computes from activities and precedence, not from a simulation or a sampled calendar.

\text{activities}=6

Starting activity

Activity A has duration 2 and no predecessor. Interpretation: it is the entry activity for this project model. Why: without a predecessor, it can start at the project origin.

d_A=2

Branching activity

Activity C has duration 4. Why: after A, the project can proceed along more than one branch. The graph matters because parallel branches can have different durations, and the later branch controls downstream starts.

d_C=4

Finish activity

Activity F has duration 2 and waits for its predecessors. Why: the project cannot finish until every required branch reaches F. That is the core scheduling intuition: a merge point waits for the latest incoming branch.

d_F=2