[sc34wg3] RE: [RDFTM] Guidelines: Editor's draft for review
Bernard Vatant
sc34wg3@isotopicmaps.org
Mon, 13 Feb 2006 10:39:42 +0100
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<font color="#000000" face="Arial" size="-1">Steve<br>
<br>
Just one or two precisions to clarify my viewpoint on an issue I have
addressed only implicitly in my previous comment. The comment was
relevant only for *subject identifiers*, not *subject locators*. To be
honest, </font><font color="#000000" face="Arial" size="-1">I've been
thinking for quite a while now that the TM distinction between subject
identifiers and subject locators is fundamentally flawed, or, to be
more accurate, that the notion of subject locator is flawed. Why? I've
been struggling for a while (2001-2002) to evangelize honestly, as the
good TM guru I was supposed to be at the time, this distinction, but I
met steady and strong uncomprehension both internally at Mondeca and
from customers'. So I began to wonder if after all this notion </font><font
face="Arial" size="-1"><font color="#000000">was not </font>going
against all kind of common sense. <font color="#000000">Practically I
decided at some point to bury this issue, so</font></font><font
color="#000000" face="Arial" size="-1"> in all Mondeca
applications and underlying TM ontologies, we've *never* used so far
subject
locators at all, and certainly will never, and are very happy with that
so far. And mind you, many of those
applications deal with subjects/resources that one could broadly call
"information resources". I have in mind the legal publishing industry,
and remember last year, working on an ontology of legal publications
for Lexis Nexis France, asking the domain experts : "The moreI work
with your industry, the less I understand what a document is, could you
help with that?". And the answer was an unanimous and laughing : "We
don't understand either." And one of them added : "In fact at some
point we had completely forbidden the use of this word...". </font><font
face="Arial" size="-1"><br>
</font><font color="#000000" face="Arial" size="-1"><br>
This was sort of conforted by recent Pat Hayes' answer [1] to Alistair
Miles asking for a formal definition of rdf:InformationResource class.
Pat explains very clearly why not only </font><font color="#000000"
face="Arial" size="-1">such a definition would not</font><font
color="#000000" face="Arial" size="-1"> make much sense, but would
even be dangerous and confusing. </font><font color="#000000"
face="Arial" size="-1">Dealing with subject locators in TM2RDF
explicitly introduces the rdftm:InformationResource </font><font
color="#000000" face="Arial" size="-1">class, so it seems to meet
similar objections. It would be very interesting of course to have
directly Pat's opinion expressed here, but the way I understand it, his
remark </font><font face="Arial" size="-1">"assertions using it are
either useless or false ..." apply the same way not only to this </font><font
color="#000000" face="Arial" size="-1">rdftm:InformationResource </font><font
color="#000000" face="Arial" size="-1">class, but incidentally to the
whole underlying notion of subject locator. </font><br>
<font color="#000000" face="Arial" size="-1"><br>
I know this might look like quite a radical viewpoint, questioning a
fundamental aspect of TMDM. I'm aware it is. I also note 'en passant'
that TMRM does not define subject locators, unless I missed something.<br>
<br>
Bernard<br>
<br>
[1] <a class="moz-txt-link-freetext" href="http://lists.w3.org/Archives/Public/public-swbp-wg/2006Feb/0011.html">http://lists.w3.org/Archives/Public/public-swbp-wg/2006Feb/0011.html</a><br>
</font><br>
Steve Pepper a écrit :
<blockquote cite="midFOEHKIENIPCJNPNFKGJNOEIGLOAC.pepper@ontopia.net"
type="cite">
<title></title>
<div><span class="326483509-11022006"><font face="Arial" size="2">Dear
Bernard,</font></span></div>
<div><span class="326483509-11022006"><font face="Arial" size="2">Thanks
for your quick feedback.</font></span></div>
<div><span class="326483509-11022006"></span> </div>
<div><span class="326483509-11022006"><font face="Arial" size="2">If
I understand you correctly, you are saying the following:</font></span></div>
<ol>
<li><span class="326483509-11022006"><font face="Arial" size="2">Our
approach regarding identity is basically sound (i.e., that it covers
all possible situations and allows for roundtripping, which were our
goals).</font></span> </li>
<li><span class="326483509-11022006"><font face="Arial" size="2">This
approach <strong>is</strong> deterministic, contrary to what the
current draft states.</font></span> </li>
<li><span class="326483509-11022006"><font face="Arial" size="2">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.</font></span></li>
</ol>
<div><span class="326483509-11022006"><font face="Arial" size="2">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?</font></span></div>
<div> </div>
<div><span class="326483509-11022006"><font face="Arial" size="2">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.</font></span></div>
<div><span class="326483509-11022006"></span> </div>
<div><span class="326483509-11022006"><font face="Arial" size="2">Steve</font></span></div>
<p><font size="2">--<br>
Steve Pepper <a class="moz-txt-link-rfc2396E" href="mailto:pepper@ontopia.net"><pepper@ontopia.net></a><br>
Chief Strategy Officer, Ontopia<br>
Convenor, ISO/IEC JTC 1/SC 34/WG 3<br>
Editor, XTM (XML Topic Maps 1.0)</font></p>
<p><em><font color="#808080" size="2">Those cartoons: The issue is
racism<span class="326483509-11022006">, not free speech</span><span
class="326483509-11022006"> --</span><br>
</font><a
href="http://www.socialistworker.co.uk/article.php?article_id=8267"><font
color="#808080" size="2">http://www.socialistworker.co.uk/article.php?article_id=8267</font></a></em></p>
<blockquote dir="ltr"
style="border-left: 2px solid rgb(0, 0, 0); padding-left: 5px; margin-left: 5px; margin-right: 0px;">
<div class="OutlookMessageHeader" dir="ltr" align="left"><font
size="2">-----Original Message-----<br>
<b>From:</b> <a class="moz-txt-link-abbreviated" href="mailto:public-swbp-wg-request@w3.org">public-swbp-wg-request@w3.org</a>
[<a class="moz-txt-link-freetext" href="mailto:public-swbp-wg-request@w3.org">mailto:public-swbp-wg-request@w3.org</a>]<b>On Behalf Of </b>Bernard
Vatant<br>
<b>Sent:</b> 10. februar 2006 16:27<br>
<b>To:</b> Steve Pepper<br>
<b>Cc:</b> SWBPD list; WG3 mail list<br>
<b>Subject:</b> Re: [RDFTM] Guidelines: Editor's draft for review<br>
<br>
</font></div>
<font face="Arial" size="-1">Hi Steve, and all RDFTM'ers<br>
<br>
First : Good job, congratulations!<br>
<br>
A first comment, guess what, on the section on identity :))<br>
</font>
<blockquote><font face="Arial" size="-1"><a>(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.</a><br>
</font></blockquote>
<font face="Arial" size="-1">And in the final section on
non-deterministic rules<br>
</font>
<blockquote>
<p><font face="Arial" size="-1"><a>(2) Topics with multiple
identifiers — because there is no deterministic way to choose the
identifier to use as the URIref of the resulting resource.<br>
</a></font></p>
</blockquote>
<font face="Arial" size="-1">I would say that this is a contrario a
completely deterministic situation. <br>
<br>
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. </font><font face="Arial" size="-1"><a>Does
this rule break the general principle "one TM subject = one RDF
resource"? I don't think so, since resources linked by </a><a>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.</a></font><br>
<font face="Arial" size="-1">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? <br>
<br>
RDF2TM : When two (or more) (individual) resources are linked by a <a>owl:sameAs
property, they generate a single topic bearing the URIref of those
resources as subject identifiers. <br>
Same question as above. How many topics do you generate from resources
linked by owl:equivalentClass or owl:equivalentProperty?<br>
</a></font>
<p><font face="Arial" size="-1">Best<br>
</font></p>
<p><font face="Arial" size="-1">Bernard</font><br>
</p>
<br>
<div class="moz-signature"> <font size="2">
<div align="left">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><strong><span
style="font-size: 11pt; color: gray; font-family: Arial;">Bernard
Vatant</span></strong></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span
style="font-size: 10pt; color: gray; font-family: Arial;"></span><span
style="font-size: 11pt; color: gray; font-family: Arial;"><O:P><font
size="2">Knowledge Engineering</font></O:P></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span
class="important1"><b><span
style="font-size: 11pt; font-family: Arial;" lang="EN"><font
color="#901b3f">Mondeca<span class="901565122-29122005"> </span></font></span></b></span><b><span
style="color: navy; font-family: Arial;"><br>
</span></b><span
style="font-size: 10pt; color: gray; font-family: Arial;">3, cité
Nollez 75018 Paris <ST1:PLACE w:st="on"><ST1:COUNTRY-REGION w:st="on">France</ST1:COUNTRY-REGION></ST1:PLACE><O:P></O:P></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span
style="font-size: 10pt; color: gray; font-family: Arial;" lang="EN-GB">Tel.
+33 (0) 871 488 459 </span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span
style="font-size: 10pt; color: gray; font-family: Arial;" lang="EN-GB">Mail:
</span><span
style="font-size: 10pt; color: gray; font-family: Arial;"><a
href="mailto:bernard.vatant@mondeca.com"><span
style="color: gray; text-decoration: none;" lang="EN-GB">bernard.vatant@mondeca.com</span></a></span><span
style="font-size: 10pt; color: gray; font-family: Arial;" lang="EN-GB"><O:P></O:P></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span
style="font-size: 10pt; color: navy; font-family: Arial;"><font
color="#000000">Web: </font><a href="http://www.mondeca.com"><span
style="color: navy;" lang="EN-GB">www.</span><span style="color: navy;">mondeca.com</span></a></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span
style="font-size: 10pt; color: navy; font-family: Arial;"><font
color="#000000">Blog : <a href="http://universimmedia.blogspot.com">universimmedia.blogspot.com</a>
</font></span></p>
</div>
</font></div>
<br>
<br>
Steve Pepper a écrit :
<blockquote
cite="midFOEHKIENIPCJNPNFKGJNEEFDLNAC.pepper@ontopia.net" type="cite">
<div><span class="095201810-10022006"><font face="Arial" size="2">I
am pleased to announce the availability of the first draft of the <strong>Guidelines
for RDF/Topic Maps Interoperability</strong> for review by the SWBPD
Working Group and the ISO Topic Maps Working Group:</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">
<a href="http://www.ontopia.net/work/guidelines.html">http://www.ontopia.net/work/guidelines.html</a></font></span></div>
<div><span class="095201810-10022006"><font face="Arial" size="2">
<a href="http://www.ontopia.net/work/guidelines.pdf">http://www.ontopia.net/work/guidelines.pdf</a></font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">The
next meeting of the editors is scheduled for February 21st and we would
be grateful for as much feedback as possible before then.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">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 (<strong>5. Translation
guidelines: formal rules</strong>). We have not yet settled on a
formalism, so we would appreciate input on (1) whether we really need
one (perhaps section<strong> 3. Informal Guidelines</strong> is
sufficient), and (2) what formalism the WGs think might be appropriate.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">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 <font
color="#ff0000">Recommendation</font> 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.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">I
would like to draw the attention of members of the <font
color="#ff0000">OEM Task Force</font> to section <strong>3.6.2 N-ary
relationships</strong> in particular. As you will see, we have based
our approach on the work done by Natasha, Alan and Pat in the document <em>Defining
N-ary Relations on the Semantic Web </em>(latest draft at <a
href="http://smi-web.stanford.edu/people/noy/nAryRelations/n-aryRelations-2nd-WD.html">http://smi-web.stanford.edu/people/noy/nAryRelations/n-aryRelations-2nd-WD.html</a>).
It seems to us that we only need to define a single class (which we
have called <font face="Courier New">rdftm:N-aryProperty</font>, for
consistency with the rest of the RDFTM Guidelines) in order to <strong>both</strong>
represent Pattern 1 (A and B) <strong>and</strong> provide the
guidance necessary to achieve RDFTM interoperability. We would
appreciate your feedback on this.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">The
work of the editors has been taking place using the University of
Bologna Wiki at <a
href="http://tesi.fabio.web.cs.unibo.it/cgi-bin/twiki/bin/view/RDFTM">http://tesi.fabio.web.cs.unibo.it/cgi-bin/twiki/bin/view/RDFTM</a>.
Minutes of our conference calls are available at <a
href="http://tesi.fabio.web.cs.unibo.it/RDFTM/MinutesOfConferenceCalls">http://tesi.fabio.web.cs.unibo.it/RDFTM/MinutesOfConferenceCalls</a>.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">We
look forward to receiving your comments.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">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.</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">Best
regards,</font></span></div>
<div><span class="095201810-10022006"></span> </div>
<div><span class="095201810-10022006"><font face="Arial" size="2">Steve</font></span></div>
<p><font size="2">--<br>
Steve Pepper <a class="moz-txt-link-rfc2396E"
href="mailto:pepper@ontopia.net"><pepper@ontopia.net></a><br>
Chief Strategy Officer, Ontopia<br>
Convenor, ISO/IEC JTC 1/SC 34/WG 3<br>
Editor, XTM (XML Topic Maps 1.0)<br>
</font></p>
</blockquote>
</blockquote>
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