Definition:
Actor in an event who initiates and carries out the event intentionally or consciously, and who exists independently of the event.
Example:
THEY decided to go.
Agent
[
+animate
|
+organization
]
Definition:
Theme characterized by information content.
Example:
Susan chitchatted with Rachel ABOUT THE PROBLEM.
Topic
Definition:
The starting point (possibly metaphoric) of an action; it exists independently of the event.
Example:
I gleaned FROM THE EVIDENCE how she did it.
Source