[topicmapmail] Two Models of Facets

[Murray Altheim]

Murray Altheim wrote:
> Okay, where are we? Continuing with this conversation...
[...]

Gah! Sloppy! Sloppy! Sloppy! Head-in-basket! the *worst* thing one
can do is mess up the syntax example! So, here's the fixed version
with the added bonus that I've included the LTM 1.2 version, which
is easier to read (new and improved!):

EXAMPLE:

   > An example in XTM, "Elvis has birthday '1935-01-08'". This could
   > be modeled as a Topic "Elvis", an Association type "has birthday",
   > and another Topic, "1935-01-08", but another way would be to
   > consider the birth date as a facet of the Topic "Elvis".

In LTM 1.2 this would be (assuming availability of the facet PSI Topics):

     [elvis = "Elvis Presley"]

     hasFacet([elvis] : faceted,    /* the topic being faceted */
              [elvis-bd] : facet )  /* the facet being added */

     [elvis-bd : birthdate]
     {elvis-bd, facetValue, [[1935-01-08]]}
     {elvis-bd, facetMinIncl, [[1800-01-01]]}
     {elvis-bd, facetMaxIncl, [[2003-11-25]]}

(I've got a simpler proposed syntax for all of this, but I'll leave
that for later.)

In XTM 1.0:

     <topic id="elvis">
       <baseName>
         <baseNameString>Elvis Presley</baseNameString>
       </baseName>
     </topic>

     <association>
       <instanceOf><!-- ........................... facet predicate 'hasFacet' -->
         <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/facets/#hasFacet"/>
       <instanceOf>
       <member><!-- ............................... facet role -->
         <roleSpec>
           <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/facets/#facet"/>
         </roleSpec>
         <topicRef xlink:href="#elvis-bd"/>
       </member>
       <member><!-- ............................... faceted role -->
         <roleSpec>
           <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/facets/#faceted"/>
         </roleSpec>
         <topicRef xlink:href="#elvis"/>
       </member>
     </association>

     <topic id="elvis-bd">
       <instanceOf><!-- ........................... facet type -->
         <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/ceryle/#birthdate"/>
       <instanceOf>
       <occurrence><!-- ........................... facet value -->
         <instanceOf>
           <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/facets/#facetValue"/>
           <!--subjectIndicatorRef xlink:href="http://www.w3.org/2001/XMLSchema#dateTime"/-->
         <instanceOf>
         <resourceData>1935-01-08</resourceData>
       </occurrence>
       <occurrence><!-- ........................... constraining facet minInclusive value -->
         <instanceOf>
           <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/facets/#facetMinIncl"/>
           <!--subjectIndicatorRef xlink:href="http://www.w3.org/2001/XMLSchema#dateTime.minInclusive"/-->
         <instanceOf>
         <resourceData>1800-01-01</resourceData>
       </occurrence>
       <occurrence><!-- ........................... constraining facet maxInclusive value -->
         <instanceOf>
           <subjectIndicatorRef xlink:href="http://purl.org/ceryle/psi/facets/#facetMaxIncl"/>
           <!-- subjectIndicatorRef xlink:href="http://www.w3.org/2001/XMLSchema#dateTime.minInclusive"/-->
         <instanceOf>
         <resourceData>2003-11-25</resourceData>
       </occurrence>
     </topic>

----

The reason for the error is that in my notes I've been playing with
XSD datatypes' facets as well, and forgot to comment out those refs.
Plus a cut-and-paste error or two, and changes to the PSI IDs.
Anyway, sorry for any confusion.

So...
   > To reiterate, I'm interested in ultimately finding out if there
   > are any fundamental reasons why we can't use the same model and
   > syntax for both Model A and Model T, and if not, what differences
   > we'd see as necessary to differentiate class-based characteristics
   > from instance-based characteristics. The subtlety of this is a bit
   > similar to that of the reification problem; we need to keep things
   > clear.

Murray

......................................................................
Murray Altheim                    http://kmi.open.ac.uk/people/murray/
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

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