(...basically, look at the aborted c5 paper....)

rationale:
  why PU's exist 
    (copy from web page)


  why they are worth modelling explicitly
    they are there anyway

    it makes it easy to manage

    it does mean that packages get released potentially multiple times.
    this is normal, however: packages need slight reconfigurations depending
    on which universe they participate in.  This is no different from
    having a separate package of gcc for every linux distro.



properties:
  can be composed to form new ones

  dependency management is simplified due to limited set of packages

  practical, as exemplified by experience with Debian and by
  the presently described implementation

  policy neutral.  each universe can have its own policies for
  what goes in, what changes are allowed, etc.

  no central control; universe-based collaboration groups
  can be built bottom-up.  especially important for allowing
  private use, e.g. for commercial activity.  further, individual
  universes with different policies may be combined, e.g. if a
  commercial work group wants to have local packages plus use
  publically available packages.
   

example configurations
  
