total float notation

In the this section of the paper we explore the third part of arrow diagram calculations, the "float" calculations. Determining the float of an activity is the reason why the forward and backward pass are perlormed. On the arrow diagram, the float is placed in a circle next to an activity's duration.

arrow diagram, total float notation

Conceptually, float represents the amount of time an activity may be delayed without impacting the overall completion of a project. For example, if two tasks were to be accomplished simultaneously and one task took 10 days and the other took 20 days, it should be obvious that: (1) the entire project will take 20 days to complete, and (2) that you do not have to start the 10 day task right away since the overall project takes 20 days. An activity may not need to start on its early event time is the idea behind float