W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > January 2003

Re: Comment on Last Call Working Draft of RDF Semantics document concerning RDFS closure rules

From: pat hayes <phayes@ai.uwf.edu>
Date: Sun, 26 Jan 2003 11:21:55 -0700
Message-Id: <p05111b19ba59d4622acd@[]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-comments@w3.org, w3c-rdfcore-wg@w3.org

>The closure rules for RDFS are incomplete.  For example,
>    ex:foo ex:prop "a" .
>    ex:foo ex:prop _:x .
>    _:x rdf:type rdfs:Resource .
>However, this does not come out of the RDFS closure rules.
>This means that the RDFS entailment lemma is false.

That is true, and I had indeed not previously noticed this case, 
which requires the notion of closure to be re-worded slightly. The 
inference can be obtained as follows:

ex:foo ex:prop "a" .
ex:foo ex:prop _:x .

is sanctioned by the general RDF entailment conditions, and the other 
triple is then inferred by the rule rdfs4b. However, this means that 
the closure rules need to be applied *after* some RDF inference is 

The definition of closure will be re-worded so as to first add all 
existential conclusions on triples involving literals, then apply the 
closure rules. This will handle this exceptional case.


IHMC					(850)434 8903 or (650)494 3973   home
40 South Alcaniz St.			(850)202 4416   office
Pensacola              			(850)202 4440   fax
FL 32501           				(850)291 0667    cell
phayes@ai.uwf.edu	          http://www.coginst.uwf.edu/~phayes
s.pam@ai.uwf.edu   for spam
Received on Sunday, 26 January 2003 13:35:58 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 14:54:03 UTC