Project Network

A project network is a graph (flow chart) depicting the sequence in which a project's terminal elements are to be completed by showing terminal elements and their dependencies.

It has two elements : Initial and terminal objects

Initial objects are also called conterminal  or universal, and terminal objects are also called final.

If an object is both initial and terminal, it is called a zero object or null object.

A terminal element is the lowest element (activity or deliverable) in a work breakdown structure; it is not further subdivided. Terminal elements are the items that are estimated in terms of resource requirements, budget and duration; linked by dependencies; and scheduled. A terminal element is sometimes called a work package, although the two terms are not synonymous