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Question about Extensional Entailment Rules

From: Nick Bassiliades <nbassili@csd.auth.gr>
Date: Thu, 26 Aug 2004 11:26:22 +0300
Message-ID: <412D9EAE.7080304@csd.auth.gr>
To: www-rdf-comments@w3.org
Hi all,

I would like to ask you whether I am missing something from the 
extensional entailment rules ext1&2
in the RDF Semantics document (http://www.w3.org/TR/rdf-mt/).

Rule ext1 says that when:
   uuu rdfs:domain vvv .
and
   vvv rdfs:subClassOf zzz .
are true, then the triple:
   uuu rdfs:domain zzz .
should be added.

However, IMHO this looks rather bizarre! This rule states that when a 
property has a certain class as a
domain, it must also have all its superclasses as a domain. I believe 
that it's the other way around:
all the subclasses of a class can be domains for the property uuu.

For example,
   uni:faculty rdfs:subClassOf uni:staff .   (/Faculty members are 
member of the staff/)
   uni:teaches rdfs:domain uni:faculty .     (/Faculty members teach/)
then we infer with rule ext1 that:
   uni:teaches rdfs:domain uni:staff .       (/All members of the staff 
can teach!/)

I would expect it to work the other way around:
   uni:lecturer rdfs:subClassOf uni:faculty .   (/Lecturers are 
//Faculty members/)
   uni:teaches rdfs:domain uni:faculty .        (/Faculty members teach/)
then we infer that:
   uni:teaches rdfs:domain uni:lecturer .       (/Lecturers // can teach/)

Am I missing something here?

Thank you in advance,

Nick Bassiliades

-- 
*********************************************************************
* Dr. Nick Bassiliades, Assistant Professor                         *
* Dept. of Informatics, Aristotle University of Thessaloniki        *
* 54124 Thessaloniki, Greece                                        *
*                                                                   *
* Tel: +302310997913   E-mail: nbassili@csd.auth.gr                 *
* Fax: +302310998419   URL: http://lpis.csd.auth.gr/people/nbassili *
*********************************************************************



Received on Thursday, 26 August 2004 08:26:28 UTC

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