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Re: RDF-ISSUE-84 (d-entailment-typed-literals): "Bug" in D-entailment with literals in non-canonical form [RDF Semantics]

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 24 Feb 2012 09:23:18 -0600
Message-Id: <3BB61448-17A6-41B0-8B8E-7E99E59EE2BE@ihmc.us>
To: RDF Working Group <public-rdf-wg@w3.org>, RDF Working Group Issue Tracker <sysbot+tracker@w3.org>

On Feb 24, 2012, at 12:43 AM, RDF Working Group Issue Tracker wrote:

> RDF-ISSUE-84 (d-entailment-typed-literals): "Bug" in D-entailment with literals in non-canonical form [RDF Semantics]
> 
> http://www.w3.org/2011/rdf-wg/track/issues/84
> 
> Raised by: Antoine Zimmermann
> On product: RDF Semantics
> 
> With the current spec, we have the following situation for D-entailment, when the datatype map contains xsd:decimal (for instance):
> 
> :foo :bar "2"^^xsd:decimal .
> 
> *does not* D-entail:
> 
> :foo :bar "2.0"^^xsd:decimal .
> 
> This is because an interpretation is defined relatively to a vocabulary V, so that only the names in V are interpreted.

Yes, but the definition of D-entailment requires the interpretations to interpret the vocabulary of literals which are meaningful under the datatype mappings in question. See http://www.w3.org/TR/rdf-mt/#defDinterp


> If a triple contains a name that is not present in V, then the triple is necessarily unsatisfied.  This is made very explicit in the RDF Semantics document:
> 
> "If the vocabulary of an RDF graph contains names that are not in the vocabulary of an interpretation I - that is, if I simply does not give a semantic value to some name that is used in the graph - then these truth-conditions will always yield the value false for some triple in the graph, and hence for the graph itself."
> 
> Since "2"^^xsd:decimal and "2.0"^^xsd:decimal are two different names (although denoting the same thing), the first triple can be satisfied by a D-interpretation that does not interpret "2.0"^^xsd:decimal,

No, because this would not be a D-interpretation. It is not defined on the required vocabulary.

Pat

> thus the second triple does not follow from the first one.

> 
> This is probably not in line with how implementations work and the problem seem to be present in OWL 2 RDF-based semantics as well.
> 
> 
> 
> 

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Received on Friday, 24 February 2012 15:23:50 UTC

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