[topicmapmail] multiple Source Locators

[Thomas B. Passin]

Lars Marius Garshol wrote:

>  - topic maps support n-ary relationships

Actually, so does rdf, de facto.  If you let a node have a type like 
what we would call an association type, and hand a number of triples off 
that node, then it looks exactly like a topic map association, where the 
rdf predicates correspond to the topic map roles.

And of course in real like, you are likely to have this show up 
frequently.  For example, think of representing a row in a relational 
database.  You would have a node for the role, and a binary association 
hangind off the row node for each column entry.  In relational database 
language, a row is termed a "relation", and that is just what it is.

In this way, rdf has no problem representing n-ary relationships, though 
there is nothing in the formal semantics that specifically bears on them.

The joke is that if you did this for a binary relationship (think of a 
2-column table), you would in effect be reifying the relationship 
("reifying" in the topic map sense"), but I have never seen this notion 
mentioned anywhere.  So rdf does has a way to provide for topic 
map-style reification after all, and it seems perfectly sensible to me. 
  Of course, standard rdf processors wouldn't quite know what you were 
up to, but it would be legal and reasonable.

Cheers,

Tom P

-- 
Thomas B. Passin
Explorer's Guide to the Semantic Web (Manning Books)
http://www.manning.com/catalog/view.php?book=passin