RDF mismatch with frame-based systems?

Up to the QL '98 workshop[1], I considered RDF[2] a hand-in-glove
fit with frame-based reasoning systems. So I was suprised
to see

	"The schemas of RDF allows hte definition of
	attributes, so called property types.
	The property types are -- in contrast to
	frame based languages like F-Logic-- general
	in the sense that they do exist independently of
	classes. Thus, it is not possible to give the same name to
	different properties for several classes if they
	have different value ranges or cardinalities."

in section 3.1 "RDF/RDFS and Frame-Logic" of Decker's paper[3]

The idiom that I'm most familiar with is from Algernon[4]:


(:slot  atom (domain  ) descriptor  ) 

      Declares a new slot and types it using domain  . Typing is
      enforced using an if-added rule. For example: 

      declares the slot has-disease to be a relation between people
      and diseases. If one then asserts: 


      Algernon concludes that p1 isa people, and d1 isa diseases. 

Is Algernon typical of the class of "frame based languages
like F-Logic" or is it different?

Is either of them or both consistent with the RDF specs?

"A property can have at most one range property."
(specifically 3.1.3)

"A property may have zero, one or more
than one class as its domain. If there is no domain property, it may be
used with any resource. If there is no domain property, it may be
used with any resource. If there is exactly one domain property, it may
only be used on instances of that class (which is the value of the
domain property). If there is more than one domain property, the
constrained property can be used with instances of any of the classes
(that are values of those domain properties). "

I'm not sure what "if there is no domain property" means
in the absense of the closed-world assumption.

Sorry these questions are sort of messy and ill-formed,
but I want to get my thoughts down before I forget, and
I'm not sure when/if I'll find time to research the question
more fully.

[1] The W3C Query Languages Workshop 
December 3rd and 4th, 1998
Boston, Massachussets 

[2] Resource Description Framework (RDF)

[3] Decker S.,Erdmann, M., Fensel, D., and Studer, R. (1999)
      Ontobroker: Ontology Based Access to Distributed and
      Semi-Structured Information. In R. Meersman et al. (eds.),
      Semantic Issues in Multimedia Systems, Kluwer Academic
      Publisher, Boston. http://www.aifb.uni-karlsruhe.de/WBS/broker. 

linked from

linked from http://www.w3.org/TandS/QL/QL98/pp.html

[4] Algernon and Access-Limited Logic

linked from http://www.w3.org/Architecture/Terms.html

Dan Connolly
phone:+1-512-310-2971 (office, mobile)

Received on Tuesday, 8 December 1998 14:04:03 UTC