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Re: Two questions on working draft 30 july 2008

From: Chris Welty <cawelty@gmail.com>
Date: Fri, 28 Aug 2009 09:27:47 -0400
Message-ID: <4A97DB53.4050108@gmail.com>
To: David Mott <MOTTD@uk.ibm.com>
CC: public-rif-comments@w3.org
Hi David,

Thanks for your question.

David Mott wrote:
 > 1) Please could you explain why condition 8 in section uses "superset 
 > leading to the comment "a rdfs:subClassOf b is true if a ## b is true".
 > Why is this not "equal to", leading to  "a rdfs:subClassOf b is true iff a ## 
b is true"?

RDFS semantics stipulates subclass to be reflexive, so for all a: a 
rdfs:subClassOf a. RIF subclass is not necessarily reflexive. You can assert 
that some class is a subclass of itself, but it isn't entailed for every class. 
Thus, every rif subclass relation is an rdfs one, but not the other way around.

 > 2) for clarity, is the sentence "Since RIF frame formulas are interpreted 
using an extension function, as in RDF " in section 4 5th para, justified by the 
condition 4 in If so, could you add a pointer?

No, those statements are justified by the RDF and RIF semantics. The "RDF&OWL" 
document just talks about combining them, and thus is just about 
combinations of RIF and RDF.

Please let us know if this is satisfactory.

Received on Friday, 28 August 2009 13:28:41 UTC

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