Basic Terminology for Dependencies and Events

The following illustration introduces some graphical symbols and terminology that is used in dependency and event analysis.

If A, B, and C are processes:

The activities A, B, and C are interdependent because they are joined by a network of dependencies.
The directed line (line with an arrowhead) from A to B represents a dependency of B on A.
The directed line from B to C represents a dependency of C on B.
An execution of B can be said to depend or enabled by A.
C depends B.
A is prerequisite to B.
B is prerequisite to C.
D and F are external objects.
The directed lines from D to A and from C to E represent information flows.
E is an event.
The directed line from E to B represents a dependency of B on an occurrence of the event E.
E initiates or enables B.
B can be said to execute in response to E.
E initiates or is prerequisite to B.