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Re: on media types for OWL (5.13)

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 31 Oct 2002 08:42:09 -0500 (EST)
Message-Id: <20021031.084209.99234954.pfps@research.bell-labs.com>
To: connolly@w3.org
Cc: hendler@cs.umd.edu, www-webont-wg@w3.org

From: Dan Connolly <connolly@w3.org>
Subject: Re: on media types for OWL (5.13)
Date: 30 Oct 2002 22:06:23 -0600

[...]

> > >   Also, if the first one was not an OWL document (i.e. was app/RDF) 
> > > how would it change the point you're trying to make?
> > 
> > Well, the whole point is that you can't tell what kind of a document it is
> > just by its contents.  If you consider the first document as RDF, then the
> > entailment would not follow.
> 
> I don't know what you mean by "consider a document as RDF",
> nor have you been explicit about which entailment relationship
> you're referring to.

Well, I think that the general idea is that the type of the document should
determine how it is processed. That is, if the document is an RDF document,
then RDF entailment is indicated; if the document is an RDFS document,
then RDFS entailment is indicated; if the document is a (Lite/Fast/Large)
OWL document, then (Lite/Fast/Large) OWL entailment is indicated.

> If the question is re-phrased in terms we use in the specs,
> it be comes clear, and it becomes orthogonal to mime types:
> 
> Does the first document simply-entail[1] the second? no.
> Does it fast-owl entail the second? yes.
> And so on.

My point is which entailment is an application supposed to use.  

> [1] http://www.w3.org/TR/2002/WD-rdf-mt-20020429/#entail
> 
> > >   Afraid I need this is words of one syllable - this conversation has 
> > > gotten above my limited level of competence on mime types
> > 
> > Well, my understanding of MIME types is also quite limited, but I believe
> > that they are supposed to tell you how to interpret the bits of a
> > document.  My point is that there is no way to distinguish between RDF/XML and
> > OWL/RDF/XML documents, and the difference matters.
> 
> I don't see any need to distinguish between RDF/XML and
> OWL/RDF/XML documents; I see only a need to distinguish
> between simple-entailment, rdfs-entailment, fast-owl
> entailment, large-owl, entailment, etc.

Yes, but how?

> I'm not really sure we're getting anywhere beyond
> my "take your pick of the 3 mime types" proposal;
> you haven't convinced me that app/owl is
> necessary, nor do I have any compelling argument
> that app/rdf is sufficient.
> 
> In case it matters, I'd be happy to put the "take
> your pick of the 3" proposal in our next WD,
> but *not* close the issue until we have
> a chance for community review... feedback
> might eliminate or endorse some of the options.

I also really don't know which way to go.  

I think I would prefer some way of identifying the formalism intended by
the document.  I think that it is not possible to distinguish based on the
information-carrying portions of the document.  So it appears to me that
MIME types are the way to go, but I'm willing to use other methods, such as
an attribute on the enclosing element.

> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/

peter
Received on Thursday, 31 October 2002 08:42:19 GMT

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