Re: Every thing is a 'thing'

* Robert Barta
>
> Right. Or we could take the viewpoint that
>
>   where
>       $thing isa tm:topic
>
> gives all topics and

The trouble with this one is that if we return the "drrho" topic here  
we claim that you are a topic, but as far as I know you're actually  
*not* part of any topic map, but rather a living, breathing person.  
So that would be semantically wrong. :-/

>   where
>       $thing isa tm:subject
>
> gives (2) or (3) above. Question is whether values are 'subjects' in
> the TMDM sense.

The easiest type of question on earth is questions of the form

   "Is X a 'subject' in the Topic Maps sense?"

The answer is always the same: yes. (Just read the definition.)

Values are subjects, you are a subject, the question of whether  
values are subjects is a subject, the bottle of beer next to my  
laptop is a subject, Topic Maps is a subject, ... "Any thing  
whatsoever," right?

>>>      ? Should all map items be an instance of tm:subject implicitly
>>>        + tm:subject is a great placeholder
>>>        - TMDM does not say it (or does it?)
>>
>> Whooops. Does this mean that you intend for it to be (2)?
>
> I'm just asking. If atomic values _are_ subjects, then it would be
> (2), right? And if not, then probably (3), I guess.

You mean the other way around, right?

Anyway, the question here isn't just what the semantics are, but also  
what we *want*. And I think we want something that produces all  
topics, period.

> The question is what should
>
>   (a)    select $x    where       $x isa tm:subject

I think I prefer (1), which was "all topics", on the grounds that

  - "isa" is an association, and associations only apply to topics,
  - the set of all topics is what we want, anyway.

>   (b)    select $x    where       $x iko tm:subject

This is the subclasses of tm:subject, right? In that case it should  
be all topic types. (Although it *could* be all types.)

> I think we shortly touched this one in Leipzig, but I am unsure
> whether this was followed up by anyone:
>
>   - is an association a specialization of subject?

Yes. (Association is a type, therefore it is a subtype of the  
universal type, which is subject.)

>   - is a topic a specialization of subject?

Ditto.

>   - is an occurrence (and a name) a specialization of association?

That's spelled out in TMDM. (And the answer is yes.)

> Things like these. So something like an "Ur-Ontology" for TMDM. I
> faintly remember that you had a blog entry in this direction but
> cannot reproduce it now.
>
> But once this is written somewhere (TMDM, TMRM, TMQL), then we would
> have a commitment.

This is the stuff I'm meant to put into the TMDM -> TMRM mapping.

--Lars M.