ISSUE-43: Subclass relationship ## in RIF-BLD

ISSUE-43: Subclass relationship ## in RIF-BLD

http://www.w3.org/2005/rules/wg/track/issues/43

Raised by: Michael Kifer
On product: Architecture

Objections have been raised to the inclusion of the subclass relationship,
a##b, in RIF-BLD on the grounds that it duplicates rdfs:subclassOf.

Defenders of this relationship state that:

1. Subclass relationship is a common and very basic concept of any
   object-oriented/frame representation, and frame representation requirement
   is in the Charter.

2. The rdfs:subclassOf relationship is not a standard subclassOf relationship.
   Using it instead of ## introduces additional axioms into the semantics,
   which are not supported by standard object-oriented languages.

3. Not including ## in the language means that systems like FLORA-2,
   Ontobroker, FLORID, etc. must invent a new dialect to exchange their
   Horn subsets just because ## is not included.

4. Excluding this construct precludes us from stating simple things like
   bar##foo (i.e., bar is a subclass of foo) without carrying the baggage
   of the additional axioms of rdfs:subclassOf.

5. ## does not preclude the use of rdfs:subclassOf for languages that want
   to use RDFS' notion of subclass.

Received on Tuesday, 16 October 2007 16:10:36 UTC