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Re: What is an OWL document? was: Re: SEM: Light review of semantics document

From: pat hayes <phayes@ai.uwf.edu>
Date: Thu, 21 Nov 2002 11:19:30 -0600
Message-Id: <p05111b1cba02c3f03eae@[10.0.100.86]>
To: "Jonathan Borden" <jonathan@openhealth.org>
Cc: www-webont-wg@w3.org

>pat hayes wrote:
>
>>  >That is to say: an OWL document is an RDF document which is interpreted
>>  >according to the OWL semantics.
>>
>>  Well, OK, but look: suppose I have a doc which contains nothing but
>>  RDF but the RDF uses terms that are defined in an OWL doc somewhere,
>>  and I want to know what media type I should say it has. Seems to me
>>  that with your scheme, it doesn't matter which I use. So why do we
>>  have the distinction? Whereas if we just say, xml means it  looks
>>  like XML, rdf means it looks like RDF, and owl means it looks like
>>  OWL, then we are giving some useful syntactic information to a parser
>>  which might need to know it.
>>
>>  Pat
>
>hmmm, since RDF/XML is XML, then RDF looks like XML hence is XML.
>ditto for OWL

Spoken by a true XML loyalist. Of course the are all XML. They are 
also all unicode character strings. But if I'm an OWL engine looking 
for OWL-expressed content, then I would like to be able to find out 
if its worth looking through this piece of XML or not. Similarly for 
RDF engines.

>
>and since OWL is RDF/XML and hence looks like RDF, then OWL is RDF
>and since Dan says that all RDF is OWL, then RDF is OWL ...
>
>so what does what something looks like tell me?
>
>I guess the first question is:
>
>How do I tell whether something is RDF or OWL? Does this distinction make
>sense?

All OWL is RDF, but an OWL engine might expect to have to do 
something extra to some  OWL/RDF which it doesn't need to do to 
non-OWL RDF.  Like, for example, parse it into OWL.

>and the second:
>
>How do I know when to apply simple RDF entailments vs. RDF Schema
>entailments vs. OWL DL entailments vs. OWL Full entailments to a particular
>RDF/XML document?
>
>Answer these questions and I can tell you what an OWL document is, and if an
>OWL document is different than an RDF document.

Seems to me that being a document type is one thing, what logic I 
decide to use on it is another.

Pat

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Received on Thursday, 21 November 2002 12:19:31 GMT

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