[Data-modeling] Multiple Fictional Universes

[Tadhg O'Higgins]

How should we treat fictional universes within other fictional 
universes? Or "alternate universes" within, e.g., the Star Trek universe?

My initial thought is to have "Parent Universe" and "Sub-universes" 
properties, but I'm not sure they cover all the cases. In addition, we 
might run into the problem of having to use the Star Trek universe as a 
hold-all, containing both the "main" Star Trek universe (which most 
people will want to see data about when they arrive at the page) and 
also the minor alternate universes (e.g. from 
<http://www.freebase.com/view/guid/9202a8c04000641f800000000021eea5>) as 
separate topics connected as sub-universes.

Any thoughts on how these relationships should be handled?

Tadhg