In sequence diagrams, what do event diagrams indicate?

In sequence diagrams, event diagrams are primarily used to illustrate the logic of usage scenarios. They depict how different objects interact with one another over time, showcasing the sequence of messages exchanged between them as a particular use case unfolds. This helps stakeholders visualize the flow of control and data, identifying how system components collaborate to perform specific functionalities in response to user interactions or other events.

By focusing on the logic of usage scenarios, these diagrams aid in clarifying the behavioral aspect of systems, making it easier for analysts and designers to understand the required interactions and conditions under which various components operate. This understanding is crucial for effectively defining requirements and ensuring that the system meets the intended purpose.

The other options, while relevant to some aspects of system analysis, do not align with the specific function of event diagrams in sequence diagrams. Instead, they address different areas such as organizational structure, inter-departmental communication, or project team roles, none of which directly relate to the detailed sequence of events and interactions depicted in event diagrams.