Different types of domain concepts

1. domain entity (dm-entity)
It corresponds to noun Dm-concept. It can be further classified into user-concept, system-concept, and ordinary entity-concept.
2. domain action (dm-action)
It corresponds to verb Dm-concept
3. domain quality (dm-quality)
It describes quality associated with dm-objects and dm-actions.
For example, in "he gently pushed the bell", "gently" is a dm-quality to "push" dm-action.

Two domain concepts will be judged as identical if they share the same name and type.