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RIF-BLD Classification

From: Chris Welty <cawelty@gmail.com>
Date: Thu, 02 Aug 2007 23:48:49 -0400
Message-ID: <46B2A5A1.6060208@gmail.com>
To: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

This is my attempt to synthesize the discussion on the recent telecon. 
  Please correct any mistakes:

The new BLD draft has two operators, for membership in a class and 
subclass.  These operators have a semantics that Michael described as 
"more minimal" than either the OWL-DL or RDFS versions.

The difference between (lets call it) rif:subclassOf and 
rdfs:subclassOf is that the latter is reflexive (every class is a 
rdfs:subclassOf itself), and of course RDF has this curious syntactic 
reflection in which any  rdfs:subclassOf triple is itself in the 
domain of interpretation.

The difference between rif:subclassOf and the OWL-DL use of 
rdfs:subclassOf is that the latter in OWL-DL is reflexive and 
extensional (such that if <A rdfs:subclassOf B> and <B rdfs:subclassOf 
A> then A=B).

The principle argument against rif:subclassOf is that RDFS and OWL-DL 
already define a subclass relations for the semantic web, and this 
would add a new one.  The restrictions on rdfs:subClass could be 
expressed as axioms or in the model theory, as they are in OWL-DL.

The principle argument for rif:subclassOf is that it is more amenable 
to interchange since it is minimal, as well as a natural part of usual 
frame style syntax.

Dr. Christopher A. Welty                    IBM Watson Research Center
+1.914.784.7055                             19 Skyline Dr.
cawelty@gmail.com                           Hawthorne, NY 10532
Received on Friday, 3 August 2007 03:49:07 UTC

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