In activity diagrams, an activity edge is a relationship between two activity nodes that you can use to represent the control flow or object flow in an activity diagram.
When a specific action in an activity is complete, the activity edge continues the flow to the next action in the sequence.
You can use two types of activity edges to model the flow in activities:
Typically, activity edges do not have names; however, you can add a name to describe the purpose of each edge.
As the following figure illustrates, an activity edge is displayed as a solid line with an open arrowhead that points in the direction of the flow.