[sc34wg3] RE: [topicmapmail] clarifications in PMTM4 1.0.2

Michel Biezunski sc34wg3@isotopicmaps.org
Thu, 26 Jul 2001 09:43:22 +0200

[Lars Marius Garshol:]
> I just went through the document again, and as far as I can tell the
> only change (or at least the only text marked with red) is the
> addition of the "Note" under 11.2.3, stating that topics can only have
> a subject indicator _or_ an addressable subject, but not both.

That's not exactly what the note says (see below).

> This seems reasonable to me in and of itself, but it does mean that
> PMTM4 seems to contradict the XTM 1.0 DTD, which allows this.

Please re-read carefully what follows. I don't see where there is
any contradiction. Can you be more specific about the alleged problem
you are referring to ? If there is a problem we need to fix it, I just don't
see it.

Here are the additions in pmtm4:

There are 2 additions:

(in 3.6)

"Only t-nodes can have addressable subjects. A-nodes cannot have, as any of
their subject identity points, subject constituting resources. (The subject
of an a-node is always non-addressable because it is a relationship; it is
not a piece of information.) It is a reportable error if, when a t-node
merges with an a-node, the resulting a-node has an addressable subject."

(in 11.2.3)

Note: The above two bullet points are intended to say that a topic's subject
can either be addressable or non-addressable, but not both. (A topic always
has exactly one subject, and no single subject can be both addressable and
non-addressable.) If the subject is addressable, then exactly one of the
topic's subject identity points must be the addressable subject (i.e., the
subject-constituting resource) itself, and, in addition, there will also be
one or more subject indicators for the same addressable subject. (The "node
demander is a subject indicator" rule guarantees that there is always at
least one subject indicator, even if the subject is addressable.) If the
subject of a topic is not addressable, then none of the identity points of
the topic can be a subject-constituting resource. Again, however, because of
the "node demander..." rule, there is always at least one subject indicator,
and there may be any number of additional subject indicators.

Now, here is the XTM DTD :

  <!ELEMENT subjectIdentity
     ( resourceRef?, ( topicRef | subjectIndicatorRef )* )
  <!ATTLIST subjectIdentity
     id              ID        #IMPLIED

Michel Biezunski, InfoLoom
Tel +33 1 44 59 84 29 Cell +33 6 03 99 25 29
Email: mb@infoloom.com  Web: www.infoloom.com