Re: Temporal validitity of subject indicators?

Patrick,

>>> Lars: What's nice about RDF: They don't merge. :) You can still get a
>>> subject-centric view from RDF (collect all statements where X is the
>>> subject or object).

>> Robert: Let me repeat: it has nothing to do with the semantic technology. The same problem applies to RDF if identifiers are reused.
>> 
>> The problem i am talking about *can* be solved by the approach i sketched. That there is other subsequent problems which arise when aggregated statements are redistributed in the eco system is a different story.

> Patrick: No, see above. The author of an SI can use it incorrectly.
> 
> Moreover, to have merging with foreign SIs at all, someone has to make a judgment that involves foreign SIs. Your second map.
> 
> How is that different from an author using foreign SIs in the first map?

Yes, i agree. A subject identifier can also become foreign to its creator for many reasons. I used two distinct people in my example because it is more clear. Most important to my approach is the separation of content and glue as described beforehand. 

In the very beginning i mentioned that this approach solves this problem *in theory*. There is problems with applying this method of which most can be solved by social conventions. The main point that i want to get across is that act of assigning a subject identifier (or reusing an existing URI in RDF) is not trivial and might have unpredictable implications due to misunderstanding which is something very human. These implications are difficult or impossible to undo. This affects both, the individuals level and the ontology level (statement types, predicates).

A very good advice in the light of this issue was given years ago on this mailing list by Bernard Vatant: if you are not a 100% sure that two things are the same, make them different. That is why i was a little surprised to see the role types merged with the topic types in the last draft of TMCL metaschema.

Kind regards,

Robert