Identity (URI) of an Object or Entity should be unambiguous and globally unique
On the Web a URI should provide an unambiguous data access path
Reference to abstract (physically inaccessible) Objects or Entities is only achievable via conduit documents that carry representations of entity descriptions (which at best are facets of an entire description)
The descriptive representations of an Object or Entity must be distinct from their URIs
Data Access mechanisms must be independent and facilitate negotiation of representation.