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Declaration consistency/RDF Parsing

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Mon, 25 Jul 2011 03:28:44 -0400
Message-ID: <CAFKQJ8=cyr4cZ87rNeCADp-tmXfxF2a-wAm6tUXVSXiFZsmmdg@mail.gmail.com>
To: public-owl-comments@w3.org
It may be worth clarifying the following:

http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/#Declaration_Consistencysays:

An ontology *O* is said to have *consistent declarations* if each IRI
*I* occurring
in the axiom closure of *O* in position of an entity with a type *T* is
declared in *O* as having type *T*. OWL 2 ontologies are not required to
have consistent declarations: an ontology *may* be used even if its
declarations are not consistent.

However, in the RDF parsing spec, it seems we *do* need declaration
consistency.

For example:

 _:x *rdf:type* *owl:Restriction* .
_:x *owl:onProperty* y .
_:x *owl:hasSelf* "true"^^*xsd:boolean* .
{ OPE(y) ≠ ε } ObjectHasSelf( OPE(y) )
Here we wouldn't say { OPE(y) ≠ ε }
If declaration consistency was optional we would only need DPE(y) = ε,
APE(y) = ε

As it is now we have "At the end of this process, the graph *G* *must* be
empty.". So if OPE(y) = ε these triples would not be parsed, we would end
parsing the RDF with the "MUST" violated. That situation is potentially
confusing [1] given "an ontology *may* be used even if its declarations are
not consistent", although technically that statement would only apply to the
*results* of the RDF parsing which are apparently always declaration
consistent.

Perhaps a note either in Syntax 5.8.2 or somewhere in Mapping to RDF Graphs.

-Alan

[1]
http://sourceforge.net/tracker/?func=detail&aid=3015732&group_id=90989&atid=595534
Received on Monday, 25 July 2011 07:29:51 GMT

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