Original discussion:

http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0603&L=dc-rdf-taskforce&T=0&P=3154
http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0603&L=dc-rdf-taskforce&T=0&P=5129
http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0603&L=dc-rdf-taskforce&T=0&P=6419
http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0603&L=dc-rdf-taskforce&T=0&P=6699

This deals with the question of how to describe related descriptions.


ons 2006-03-29 klockan 18:20 +0100 skrev Pete Johnston:
> > Note also that the DCAM uses rdfs:seeAlso for related descriptions in
> > one of the examples... 
> 
> Only in the Appendix, so I've been ignoring that. Ignoring it very hard, 
> in fact. ;-)
> 
> I'm not even sure what the object of that rdfs:seeAlso is referring to 
> (in DCAM terms): a description set, a record?
> 
> Seriously, I've been working on the basis that the only way to interpret 
> "related description" is as applying to another description within the 
> same description set. That is the scope of the "description model", if 
> you like. There's nothing in the model that enables me to reference 
> other description sets or descriptions within other description sets.
> 
> There may well be a description in description set B of something which 
> is a value in a description in description set A - but it's just another 
> description. Given that a description may not include a resource URI, I 
> don't understand how we can represent any explicit relationship between 
> a value in description set A and a description in description set B (in 
> much the same way that you can't say anything about the relationship 
> between two blank nodes in two separate RDF graphs?)

No, and please don't try :-) But if the value has a URI, and we have a
URI for a separate description, there's no harm done in supplying that
URI, is there? 

> 
> Also rdfs:seeAlso doesn't say "there are more triples with resource:X as 
> subject over here"; it's much vaguer than that.
> 
> http://www.w3.org/TR/rdf-schema/#ch_seealso
> 
> says
> 
> ==
> rdfs:seeAlso is an instance of rdf:Property that is used to indicate a 
> resource that might provide additional information about the subject 
> resource.
> 
> and
> 
> It may be possible to retrieve representations of O from the Web, but 
> this is not required. When such representations may be retrieved, no 
> constraints are placed on the format of those representations.
> ===
> 
> If we _are_ saying the notion of "related descriptions" has to cover the 
> case of descriptions in other description sets, then to be honest I'm 
> struggling to see how we do that (unless we introduce URIs for 
> descriptions in the DCAM).

>From DCAM:
"Encoding guidelines should also indicate whether any rich
representations or related descriptions associated with a statement are
embedded within the record or are encoded in a separate record and
linked to it using a URI reference."

So I actually suggest allowing two mechanisms for related descriptions
in RDF

* using blank nodes within the same descriptions. No property needed.
* using a URI for the value, and using rdfs:seeAlso to reference a
separate description. No guarantees what it contains, but I can't see it
doing much harm, right?

Do you see a major issue with this approach?

/Mikael

> 
> Pete
-- 
Plus ça change, plus c'est la même chose