Composition of Communities
 
 
Communities can be composed in various ways:
- one or more communities can be abstracted as objects which fill roles in a larger community;
 - one or more objects can fill roles in several different communities;
 - a role in one community can be associated directly with a role in another community;
 - a role type can be defined directly to be a community type.
 
To some extent, these are matters of emphasis.