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Re: rdf:List RE: timbl-03

From: Jim Hendler <hendler@cs.umd.edu>
Date: Tue, 6 May 2003 07:32:25 -0400
Message-Id: <p05200f03badd4c5f5764@[10.0.1.2]>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Cc: webont <www-webont-wg@w3.org>

>(copied from rdf core)
>>  I personally agree
>>  with Tim that these (type List) triples are redundant, and I would
>>  bet that the OWL stuff, even if it does need them, could be trivially
>>  rewritten so that it did not. I was hoping that we could get back to
>>  Peter and find out whether he thought the problem was serious.
>
>
>Peter punts the problem back to me - since I am the most recent person on
>record as arguing for type triples in general (in OWL DL).
>
>Here are my thoughts:
>
>1: this is merely aesthetic either way
>    People who don't/do want the type triples can have what they want simply
>by not using the rdf:parseType="Collection" syntax (whichever way we
>decide).
>
>2: the triples *are* redundant
>    It is easy to automatically add them; or for that matter, automatically
>remove them.
>
>3: the construct was added for OWL, and so the aesthetic judgement as to
>whether they should be there or not in the convenience
>rdf:parseType="Collection" syntax, should be made by WebOnt.
>
>4: Given that in OWL DL and OWL Lite many type triples are needed, it is, in
>my opinion, more aesthetic, to have these type triples also for Lists. The
>need for type triples is principally to distinguish the various types of
>user defined in Property in OWL Lite and OWL DL.
>
>Jeremy

Jeremy - I concur w/you.  Also, I think that removing these triples, 
and then having to explain the differences everywhere would be 
painful -- would require us to carefully go through S&AS and other 
documents making sure that everywhere we discuss typing or lists we 
mention this.  I think it would be easier for RDF to leave these in 
then for us to remove them - however, I also agree it is not a make 
or break issue since they are easily added.

here's a question -- if RDF allows these triples and OWL requires 
them, does that cause a layering issue?  That is, could RDF say 
"SHOULD" or "MAY" instead of must, with a note that for compatibility 
with OWL it is recommended?  Collections without the rdf:list will 
still be in OWL Full, and it would be an easy thing to add these 
triples into a "MakeOwlDL" program that would read an RDF document 
and generate a legal OWL DL graph for it  (something I'm assuming 
will need to exist to add annotations and the like to RDF "data" 
documents)


  -JH

-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
http://www.cs.umd.edu/users/hendler
Received on Tuesday, 6 May 2003 07:32:39 GMT

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