[sc34wg3] TNC backward compatibility

[Nikita Ogievetsky]

Steve Pepper wrote:
> At 21:36 05.03.2003 -0800, Nikita Ogievetsky wrote:
> > > So the default should be that the TNC is not turned on by default.
> >
> >I am staying with YES because otherwise we are not backward compatible.
>
> We have a backwards compatibility issue anyway, because a lot of people
> simply ignored the TNC. Now we need to make sure that we don't perpetuate
> the confusion. In my opinion the default should be the general case,
> which is NO. This will be easier for people to understand and less prone
> to error.

Hmmm... I see your point. But standard said that TNC is always ON.
As far as I understand, that dictates what is backward compatible with the
standard and what is not.

> >Probably I tend to agree with Lars that neither one merges.
>
> I agree.
>
> > > By the way, the phrase "controlled vocabulary type" is a bit
constricting.
> > > The PSI defined in the SAM has the following identifier:
> > >
> > >    http://psi.topicmaps.org/sam/1.0/#unique-characteristic
> > >
> > > so I suggest we talk about "unique characteristic types" instead.
> >
> >Yes, I remember that. That also allows us to use scopes on
> >subjectIndicators.
>
> WHAT?

That is exactly my point :-)

> You must explain this. I don't see how this affects scopes
> on subject indicators.

I mean that one can now use occurrences instead  of subjectIdentity.
The distinction becomes very fragile and scary.
For example one can use occurrence of type "subjecIndicator".
BTW, in this case we are getting very close to my RDF Topic Maps schema.
But I am not sure that we want to go there. 
It may change the way people work with Topic Maps.
May be I am exaggerating?

> >I am asking this question again because in this case subjectIdentity
> >becomes syntactic sugar as we can use occurrences instead.
> >I just want to make sure that everybody understand these consequences.
>
> I'm not sure I'm willing to accept that without a *lot* more thought.
> Given the crucial role of subject indicators, this could have quite
> far-reaching consequences. I think we want to keep the notion of
> subject identification as something quite separate, even though the
> effects (in terms of merging) have points in common.

I agree. And that is why I am bringing this up.
That is why some time ago I said that we are about to open a Pandora box
if we do not think about this very carefully now.

--Nikita.

Nikita Ogievetsky, nogievet@cogx.com;
Cogitech Inc.        http://www.cogx.com
Topic Maps Tutorials and Consulting.
phone:  1 (917) 406 - 8734