fulfilment of my action of today

The following is in fulfilment of my action from today (not yet recorded in
the action tracker).


	--michael  



Rumblings on why we need classification terms in RIF
(and why RDF's vocab should not be used)
===================================================

Two issues: whether we should define facilities for expressing some data
model stuff and whether we should use rdfs for this.

Rationale:
   If we do not have such constructs then everybody will be inventing their
   own. People will not be able to specify any part of their data model in RIF
   which will reduce the usefulness of RIF as an exchange language.

Why it is not good to use RDF's facilities to define class hierarchies.:
   RDF is a foreign language whose semantics is burdened with non-standard
   things. For instance, subclass is reflexive.

   This is bad because not every language out there uses reflexive subclasses.
   For instance, if we map, say, FLORA-2's subclass relationship to RDFS's then
   in the translation (RIF) the query whether foo is a subclass of foo will
   say "yes" but in FLORA-2 it will say "no".

   Let's look at some other examples, like ILOG. From my limited experience
   with it, I remember that it uses Java as its data model. So, suppose
   there is a class foo in ILOG, which comes from Java. An ILOG set of
   rules must not derive "foo sub foo" because this is not true in the data
   model. However, it we translate Java subclass relationship into
   rdfs:subclassOf then the resulting RIF translation should generate "foo
   sub foo". (In truth, as I recall, ILOG does not have "sub" in the heads
   of the rules, but it is easy to imagine that next year ILOG is extended
   with something like a query facility. Then their stock will plummet
   because their rule sets will not be faithfully exchangeable through RIF
   :-)

Received on Tuesday, 14 August 2007 19:12:52 UTC