[sc34wg3] occurrence - basename fuzzy boarder

[Lars Marius Garshol]

I don't think the problem with your fuzzy boarder is all that hard,
really. Just tell him to shave, or, if he refuses, use an electric
shaver on him.

;-)

* Bernard Vatant
|
| Now that TNC is relaxed and typing of names is allowed, the (already
| fuzzy) boarder between names and occurrences seems to fade away a
| little more. 
|
| And well, that's good news for those who have always considered this
| boarder to be a syntactic answer to a non-question :) 

I agree that this change is likely to make people ask what the
distinction is supposed to be. The SAM answers that question as
follows:

  "A base name is a name or label for a subject, expressed as a
  string. That is, it is something that identifies the subject (though
  not necessarily uniquely) and can be used as a label for the subject
  in user interfaces. The notion of a base name corresponds closely to
  the common sense notion of a name. Suitable base names for people,
  countries, and organizations are their names, while base names for
  documents, musical works, and movies might be their titles. Base
  names may have variant names, which are alternative forms of the
  base name that may be more appropriate in specific contexts."

  "An occurrence is a relationship between a subject and an
  information resource. The precise nature of this relationship is
  described by the occurrence type, a subject which is attached to the
  occurrence. Occurrences are generally used to attach information
  resources to the subjects they are relevant to. Note that the
  occurrence is properly not the resource, but the relationship
  between it and the subject. The information resource may either be a
  string inside the topic map or an external information resource."

That gives us something of a line between the two, doesn't it?

| Let's say occurrences and basenames together form a class of
| "information items". We can define at least two clear orthogonal
| subclasses - orthogonal to each other, more clearly defined than,
| and orthogonal to, the fuzzy name-occurrence classification.

Actually, this is the way it has been seen for a long time, that
occurrences are a specialization of associations, and that base names
are a specialization of occurrences. The SAM does not express this
since we didn't want to encumber it with the notion of subclassing,
but we could still make this explicit in the prose.

The conceptual model for TMs in XTM doesn't make this clear, which I
think it ought to have done.
 
| 1. Identifier vs Non-identifier
| Some types of names (e.g. codes) will be used as unique identifiers,
| and some will not.  Some types of occurrences could also be used as
| unique identifiers (think about biometric identifiers,
| e.g. fingerprints), and some should not.  And it figures: where is
| the boarder between this name-occurrence superclass and subject
| indicators for that matter?

It's a good question. You can see subject indicators as an unscopeable
occurrence type, and the same for subject addresses. This train of
thought, if followed to the end essentially leads to RDF, or variants
thereof, such as the RM. I've been down this road many times myself,
but always come to the conclusion that the distinctions made in the
current topic map model are actually very helpful for human beings,
and sometimes also for machines.

If you think differently of this I'd love to hear why.
 
| 2. Internal vs External
| There is more difference between an external occurrence of type
| e.g. "Home Page" defined by a <resourceRef> link and an internal
| occurrence of type "Short Description" defined by a <resourceData>,
| than between the same "Short Description" and some basename of type
| "Long Name".

That's true structurally, but not semantically.
 
| Of course following this track would lead to something hardly
| compatible with XTM 1.0 syntax, but maybe compatible with the
| Reference Model. For SAM I don't figure clearly.

SAM would be changed to reflect those changes, if any are indeed
made...

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
ISO SC34/WG3, OASIS GeoLang TC        <URL: http://www.garshol.priv.no >