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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 3.2.1.2 uses "superset 
of"
 > 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 3.2.1.2? 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 3.2.1.2 is just about 
combinations of RIF and RDF.

Please let us know if this is satisfactory.

-The RIF WG
Received on Friday, 28 August 2009 13:28:41 GMT

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