[Bug 5384] Uniqueness of alias URIs

http://www.w3.org/Bugs/Public/show_bug.cgi?id=5384

           Summary: Uniqueness of alias URIs
           Product: SML
           Version: unspecified
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Interchange Format
        AssignedTo: cmsmcq@w3.org
        ReportedBy: kirk.wilson@ca.com
         QAContact: public-sml@w3.org


The following statement (actually three) statements in section 5.3.2 of SML-IF
seem to be equivalent:

Each member of the set of all alias URIs in an SML-IF document MUST be unique.
That is, no two alias URIs in a given SML-IF document may be equivalent.

All alias URIs in an SML-IF document MUST be unique.

Is there a difference?  (If so, it should be made more explicit.)