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RE: [RDFTM] Guidelines: Editor's draft for review

From: Steve Pepper <pepper@ontopia.net>
Date: Sat, 11 Feb 2006 10:44:04 +0100
To: "Bernard Vatant" <bernard.vatant@mondeca.com>
Cc: "SWBPD list" <public-swbp-wg@w3.org>, "WG3 mail list" <sc34wg3@isotopicmaps.org>
Message-ID: <FOEHKIENIPCJNPNFKGJNOEIGLOAC.pepper@ontopia.net>
Dear Bernard,

Thanks for your quick feedback.

If I understand you correctly, you are saying the following:
  1.. Our approach regarding identity is basically sound (i.e., that it covers all possible situations and allows for
roundtripping, which were our goals).
  2.. This approach is deterministic, contrary to what the current draft states.
  3.. We should consider offering an alternative for people who need to stay in OWL-DL, by allowing the use of
owl:equivalentClass and owl:equivalentProperty in addition to owl:sameAs.
Re. #2: Is it true to say that the result of TM2RDF translations will be deterministic in terms of the abstract model,
but not in terms of the syntactic representation?

We will discuss your input at the next editors' meeting and adjust the draft accordingly. If you have any more feedback,
we would be most grateful.

Steve
--
Steve Pepper <pepper@ontopia.net>
Chief Strategy Officer, Ontopia
Convenor, ISO/IEC JTC 1/SC 34/WG 3
Editor, XTM (XML Topic Maps 1.0)

Those cartoons: The issue is racism, not free speech --
http://www.socialistworker.co.uk/article.php?article_id=8267

  -----Original Message-----
  From: public-swbp-wg-request@w3.org [mailto:public-swbp-wg-request@w3.org]On Behalf Of Bernard Vatant
  Sent: 10. februar 2006 16:27
  To: Steve Pepper
  Cc: SWBPD list; WG3 mail list
  Subject: Re: [RDFTM] Guidelines: Editor's draft for review


  Hi Steve, and all RDFTM'ers

  First : Good job, congratulations!

  A first comment, guess what, on the section on identity :))

    (1) If the topic has one or more subject identifiers and no subject locators, one subject identifier (chosen at
random) becomes the URIref of the resource. Additional subject identifiers become owl:sameAs properties.

  And in the final section on non-deterministic rules

    (2) Topics with multiple identifiers — because there is no deterministic way to choose the identifier to use as the
URIref of the resulting resource.


  I would say that this is a contrario a completely deterministic situation.

  TM2RDF : A topic with several subject identifiers should map to *one RDF resource per subject identifier*, those being
linked to each other by owl:sameAs relationships. There is no choice to be made (random or not) of one URIref over
another. Actually there is one single resource, but chosing one URIref as an arbitrary "preferred one" so to speak, does
not make much sense. Does this rule break the general principle "one TM subject = one RDF resource"? I don't think so,
since resources linked by owl:sameAs properties just seem to be different because they have distinct URIref, but are
actually one single resource. http://www.w3.org/TR/owl-ref/#IndividualIdentity is crystal clear about that.
  I suppose you are well aware of the consequences in terms of the resulting species of OWL, of this systematic use of
owl:sameAs. If the resources generated are classes or properties, they will also be individuals due to the semantics of
owl:sameAs, so you are in OWL-Full. What about a possible escape rule in that case, which would be to generate
owl:equivalentClass or owl:equivalentProperty predicates instead of owl:sameAs? Did you discuss this option?

  RDF2TM : When two (or more) (individual) resources are linked by a owl:sameAs property, they generate a single topic
bearing the URIref of those resources as subject identifiers.
  Same question as above. How many topics do you generate from resources linked by owl:equivalentClass or
owl:equivalentProperty?

  Best


  Bernard




  Bernard Vatant

  Knowledge Engineering

  Mondeca
  3, cité Nollez 75018 Paris France

  Tel. +33 (0) 871 488 459

  Mail: bernard.vatant@mondeca.com

  Web: www.mondeca.com

  Blog : universimmedia.blogspot.com



  Steve Pepper a écrit :
    I am pleased to announce the availability of the first draft of the Guidelines for RDF/Topic Maps Interoperability
for review by the SWBPD Working Group and the ISO Topic Maps Working Group:

       http://www.ontopia.net/work/guidelines.html
       http://www.ontopia.net/work/guidelines.pdf

    The next meeting of the editors is scheduled for February 21st and we would be grateful for as much feedback as
possible before then.

    The current draft is essentially complete, except for a number of issues (all clearly marked in the document), and
the section on the formal specification of the translation rules (5. Translation guidelines: formal rules). We have not
yet settled on a formalism, so we would appreciate input on (1) whether we really need one (perhaps section 3. Informal
Guidelines is sufficient), and (2) what formalism the WGs think might be appropriate.

    In addition to comments on the details of the translation rules, the examples, and the general approach, we would
like feedback on whether the SWBPD thinks this document should aim to become a Recommendation or just a Note. My
personal opinion is that status as a Recommendation would do a lot to enhance the "prestige" of the Guidelines and thus
encourage wider adoption.

    I would like to draw the attention of members of the OEM Task Force to section 3.6.2 N-ary relationships in
particular. As you will see, we have based our approach on the work done by Natasha, Alan and Pat in the document
Defining N-ary Relations on the Semantic Web (latest draft at
http://smi-web.stanford.edu/people/noy/nAryRelations/n-aryRelations-2nd-WD.html). It seems to us that we only need to
define a single class (which we have called rdftm:N-aryProperty, for consistency with the rest of the RDFTM Guidelines)
in order to both represent Pattern 1 (A and B) and provide the guidance necessary to achieve RDFTM interoperability. We
would appreciate your feedback on this.

    The work of the editors has been taking place using the University of Bologna Wiki at
http://tesi.fabio.web.cs.unibo.it/cgi-bin/twiki/bin/view/RDFTM. Minutes of our conference calls are available at
http://tesi.fabio.web.cs.unibo.it/RDFTM/MinutesOfConferenceCalls.

    We look forward to receiving your comments.

    Finally, let me take this opportunity to apologize for my lack of active participation in the SWBPD WG during the
last months: I have been off sick for quite a while. I will try to ensure that at least one of the RDFTM editors
participates in WG telecons from now on.

    Best regards,

    Steve
    --
    Steve Pepper <pepper@ontopia.net>
    Chief Strategy Officer, Ontopia
    Convenor, ISO/IEC JTC 1/SC 34/WG 3
    Editor, XTM (XML Topic Maps 1.0)
Received on Saturday, 11 February 2006 09:44:18 UTC

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