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Re: Proposed Consensus Review of RDF Core Documents

From: Jim Hendler <hendler@cs.umd.edu>
Date: Thu, 20 Feb 2003 09:25:40 -0500
Message-Id: <p05200f72ba7a9417f40f@[]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-webont-wg@w3.org

At 6:34 -0500 2/20/03, Peter F. Patel-Schneider wrote:
>  > i. Design of rdf:XMLLiteral and rdf:parseType="Literal":
>>  The full integration of this feature of RDF into OWL necessitates that the
>>  denotation in the domain of discourse be fully defined by the source RDF/XML
>>  file. We therefore request that you remove sufficient implementation
>>  variability to ensure that this is the case.  An example fix would be
>>  to require an RDF/XML parser to use a specific canonicalization on
>>  input.
>>  We have resolved that rdf:XMLLiteral will be a built-in datatype in
>>  OWL Lite, OWL DL and OWL Full contingent on a satisfactory response
>>  from RDF Core WG on this comment.
>I don't remember this resolution.

I think this was Guus' attempt to capture what was discussed last 
week, I can remove it or someone can suggest a better sentence to you.

>>  ii.Constraints on rdf:parsetype="Collection"
>>  We would prefer that rdf:parsetype="Collection" would be allowed to
>>  be a list of literals, not just a list of RDF node elements.  This,
>>  would permit some constructs in OWL that are difficult under the
>>  current design.
>>  -------------------------------------------
>>  Consensus comments on the RDF Concepts Document
>>  --------------------------------------------
>>  We believe the RDF Concepts Document is a useful document and helpful
>>  in understanding RDF and its use.  However, out Working Group did
>>  have some concerns with respect to the issue of social meaning as
>>  discussed in this document.
>>  The Web Ontology WG has mixed views on this issue and could not agree
>>  on a specific consensus response in the time available.  However, we
>>  note that a number of participants in the Webont WG have reservations
>Add ``strong'', perhaps?

my general preference would be to leave it as it is (more balanced 
give the WG doesn't have consensus), but I wouldn't object if the 
group wants to add it.

>  > about the RDF view on the social meaning of RDF. For example, it was
>>  felt by some to be unacceptable that two classes that differ only in
>>  their rdfs:comment content would not entail each other.
>This issue with rdfs:comment is completely different.  rdfs:comment does
>impinge strongly on social meaning, but the issue of non-entailment here is
>about formal meaning, not social meaning.

If someone will offer alternate wording I will be happy to consider 
it, otherwise I can just remove this sentence.

>  > We did reach consensus to request that the wording in the RDF Schema
>>  and the RDF Concepts documents be rephrased to explain this issue,
>>  and particularly its impact, more clearly, as this has ramifications
>>  on other languages, such as OWL, which are extensions to RDF.
>Which issue?  There are two here.

what two? the existance of social meaning and the impact of comments 
on formal entailment?  If so, I can rewrite

>  > -------------------------------------------
>>  Consensus comments on the RDF Schema Document
>>  --------------------------------------------
>>  We believe that the design of the language, as reflected in the LC
>>  documents, is such that OWL can appropriately use RDF Schema and
>>  endorse this design.
>>  Raphael Volz of our group has prepared a detailed review of this
>>  document which he will send to the RDF Core WG.  The Web Ontology
>>  Working Group agrees with the spirit of his review and summarizes our
>>  comments below:
>>  i. Although this document is called RDF Schema we think that the
>>  title "RDF Vocabulary Description Language" would be clearer, and
>>  make the difference from XML Schema (used for validation) more
>>  evident.
>>  ii. The current design does not specify what the behavior is for
>>  domain/range constraints stated on super-properties wrt. to
>>  subproperties.  We would request that a default behavior be specified.
>This paragraph does not address the issue that Raphael brought up.  The
>interaction between domain/range constraints and sub-/super-properties is
>well specified in the formal semantics, and not a separate problem.  The
>problem has to do with Section 4 of the RDF Schema document, which vaguely
>talks about RDF applications using domain/range constraints for things like
>document validity checking.

I copied it from Raphael and edited for English, obviously I missed 
the import.  I will be happy to either remove this or, if someone 
will suggest a short (1-2 sentence) summary of the issue, I will be 
willing to consider that.

>  > -------------------------------------------
>>  Consensus comments on the RDF Semantics document
>>  --------------------------------------------
>>  We believe that the design of the semantics, as reflected in the LC
>>  documents, is such that OWL will be able to layer appropriately.
>The basic design of the semantics may be suitable, but there are many
>problems in the details that affect OWL.  It might be able to layer OWL on
>the semantics as described in the RDF Semantics last call working draft,
>but it would require considerable work on our part to get around the errors
>in that document.

But that is exactly what I said in the next sentence

>>  However, we have a number of concerns that need to be addressed to
>>  improve the document (and, in particular, to fix some inconsistencies
>>  in the current document).
>>  Herman ter Horst of our group has prepared a detailed review of this
>>  document itemizing inconsistencies he has found.  The Web Ontology WG
>>  endorses the spirit of his review, and has asked Herman to help
>>  insure that the final RDF Semantics document is edited to fix the
>>  inconsistencies and editorial issues that he identifies.
>You should mention here the many errors that I have found in this document,
>most of which have been verified by Pat.  We might want to discuss my
>current view of the way forward with respect to the RDF Semantics document
>at the teleconference today.

How about if I add that we expect you (the editor of the OWL Semantic 
Document) to work with their editor (i.e. make sure you and Herman 
both work with him).  Pat has already agreed to work with us on the 
post-LC document, so we don't need to be overly prescriptive in our 
response -- Herman's long list of comments, and yours already 
submitted to RDF Core, serve that purpose.


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)
Received on Thursday, 20 February 2003 09:25:52 UTC

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