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Re: DRAFT response to comment #54, Jan Wielemaker

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Sat, 14 Feb 2009 18:23:07 -0500 (EST)
Message-Id: <20090214.182307.228825890.pfps@research.bell-labs.com>
To: ivan@w3.org
Cc: public-owl-wg@w3.org
On further reflection, I do not at this time support a response that
even alludes to putting multi-syntax formats into Syntax, at least
without some *very* strong caveats. 

As well, Jan does not appear to be confused in the way you mention.  He
is entirely correct that OWL2 provides a direct semantics for a non-RDF
syntax.  This has always been the case since the beginnings of OWL.
(The precursors of OWL didn't even have an RDF-compatible semantics
(partly because there was then no RDF semantics).)  The only change in
OWL 2 is that there is now a native XML syntax that is rec-track, as
opposed to a note.

Jan is confused in other ways, including in his view of the Semantic Web
as being only and always based on triples.  In fact, the standard view
of triple-meaning is insufficient to support the as-yet-unimplemented
levels of the Semantic Web stack.  Jan's toolchain will have to be
fundamentally changed at some point in the future.  The history of OWL
is to a large extent dominated by the attempt to keep Jan's toolchain as
intact as possible while still admitting effective ontology reasoning
for those who care.  If this message is not getting through, then
perhaps it is not worthwhile to continue the effort.

All this said, I do not know how we should reply to Jan.  Acquainting
him with the stark facts of representation and logical paradox may not
be effective.  Maybe we could say that the two mappings 
	Functional Syntax -> Direct Semantics -> Inferences
and
	Functional Syntax -> RDF -> RDF-Based Semantics -> Inferences
commute as much as possible while retaining effective ontological
reasoning, but, again, I am not sure that this is going to be
effective. 

Peter F. Patel-Schneider
Bell Labs Research


From: Ivan Herman <ivan@w3.org>
Subject: DRAFT response to comment #54, Jan Wielemaker
Date: Wed, 11 Feb 2009 11:38:55 +0100

> This response is, actually, a possible pattern for a number of other
> comments on the exact role of OWL/XML. Ie, if this is fine for the
> group, we may want to reuse, essentially, the same text for a number of
> others (to be exactly identified).
> 
> The reason I chose this one is because Jan did _not_ question the rec
> track aspect of OWL/XML per se (in contrast to, eg, the corresponding
> UvA comment). In this sense this one is simpler...
> 
> Here is the proposed text. I have also updated
> http://www.w3.org/2007/OWL/wiki/LC_Responses/JR8.
> 
> Ivan
> 
> ========
> 
> Dear Jan,
> 
> Thank you for your comment
> 
> <http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0069.html>
> on the OWL 2 Web Ontology Language last call drafts.
> 
> Unfortunately, your comment is based on a confusion, which is our fault
> in not conveying the message clearly enough. The technical fact is that
> there is no change between OWL 1 and OWL 2 in terms of the stack you
> refer to in your comment.
> 
> Indeed, Section 2.1 of the Conformance and Test Cases document states
> the following:
> 
> "Several syntaxes have been defined for OWL 2 ontology documents, some
> or all of which could be used by OWL 2 tools for exchanging documents.
> However, conformant OWL 2 tools that take ontology documents as input(s)
> must accept ontology documents using the RDF/XML serialization [OWL 2
> Mapping to RDF Graphs], and conformant OWL 2 tools that publish ontology
> documents must, if possible, be able to publish them in the RDF/XML
> serialization if asked to do so (e.g., via HTTP content negotiation)."
> 
> See:
> 
> http://www.w3.org/TR/2008/WD-owl2-test-20081202/#Conformance_.28Normative.29
> 
> In other words, the only _required_ exchange syntax among OWL 2 tools is
> based on RDF and is RDF/XML (the only small caveat, referred to by the
> 'if possible' remark in the text, is that there are valid RDF graphs
> that cannot be serialized into RDF/XML, eg, if complex URI-s are used
> for property IDs). Ie, the situation has _not_ changed compared to OWL 1.
> 
> The confusion obviously comes from the fact that the OWL/XML syntax,
> which was published as a note[1] for OWL 1, is now on Recommendation
> track. OWL/XML for OWL 1 was an optional feature that OWL 1 tools could
> implement if they wished to do so. The fact that OWL/XML is now planned
> as a recommendation has not changed this.
> 
> All that being said, the Working Group recognizes that this issue may
> lead to confusion, as witnessed by a number of comments that expressed
> the same concerns as yours. The group will take appropriate steps in
> conveying this information better by, eg, including multi-syntax formats
> into the functional specification, or making the situation clearer in
> the appropriate status sections. Details of these steps are not yet
> decided at this time.
> 
> [1] http://www.w3.org/TR/owl-xmlsyntax/
> 
> Please acknowledge receipt of this email to
> <mailto:public-owl-comments@w3.org> (replying to this email should
> suffice). In your acknowledgment please let us know whether or not you
> are satisfied with the working group's response to your comment.
> 
> Regards,
> Ivan Herman
> on behalf of the W3C OWL Working Group
> 
> ===========
> -- 
> 
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Saturday, 14 February 2009 23:23:32 GMT

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