On project representation and activity floats

Abstract EN

Activity floats are usually determined from the earliest and latest event realization times provided by the standard CPM-algorithm.

We show that such an approach may lead to free, safety, and interference floats that vary for different activity-on-arc representations of the same project.

This occurs due to the need for dummy activities.

Moreover, none of the float values may coincide with the corresponding values obtained from the unique activity-on-node project representation, which are the correct values for all types of floats.

We propose a simple modification of the definition of node earliest and latest realization times which allows us to avoid the observed discrepancies under all activity-on-arc representations.