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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 11:03:14 -0600
Cc: public-rdf-wg@w3.org
Message-Id: <650498B7-8714-48E6-92C9-B72D3EDBF671@ihmc.us>
To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
Yes you may be right. Give me a day to check out the details and then probably follow your suggestion. I think this happened because in one incarnation of the sematnics, 'names' were only UIRrefs. However, as a general change, I would like to make all RDF interpretations give a meaning to all IRIs, so that there is no need to mention the vocabulary V all the time. This will simplify a lot of arcane mathematical detail and edge cases, and might fix this one as well.

Pat
 
On Feb 24, 2012, at 9:52 AM, Antoine Zimmermann wrote:

> I don't read this in the same way.
> 
> Here is the text:
> 
> "If D is a datatype map, a D-interpretation of a vocabulary V is any rdfs-interpretation I of V union {aaa: < aaa, x > in D for some x } which satisfies the following extra conditions for every pair < aaa, x > in D:"
> 
> 
> So the interpretation interprets the things in V (whatever V is) and it interprets the datatype URIs. It does not necessarily interpret all the literals in the lexical space of all datatypes in D.
> 
> and the condition on literals say (I emphasize *in V*):
> 
> "if <aaa,x> is in D then for any typed literal "sss"^^ddd ***in V*** with I(ddd) = x ,
>   if sss is in the lexical space of x then IL("sss"^^ddd) = L2V(x)(sss), otherwise IL("sss"^^ddd) is not in LV"
> 
> 
> My suggestion is to simply say that:
> 
> "If D is a datatype map, a D-interpretation of a vocabulary V is any rdfs-interpretation I of V union {aaa: < aaa, x > in D for some x } union {"lit"^^aaa: lit in LS(d) for some <aaa, d> in D } which satisfies the following extra conditions for every pair < aaa, x > in D:"
> 
> and we add the following condition:
> 
> "if <aaa,x> is in D then for any typed literal "sss"^^ddd such that sss in LS(x),
>   IL("sss"^^ddd) = L2V(x)(sss)"
> 
> 
> That is, we force interpretations to interpret all literals in datatypes of D. It's probably what was initially assumed but it's better to make it explicit.
> 
> 
> 
> AZ
> 
> 
> Le 24/02/2012 16:23, Pat Hayes a écrit :
>> 
>> 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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>> 
>> 
>> 
>> 
>> 
>> 
>> 
> 
> -- 
> Antoine Zimmermann
> ISCOD / LSTI - Institut Henri Fayol
> École Nationale Supérieure des Mines de Saint-Étienne
> 158 cours Fauriel
> 42023 Saint-Étienne Cedex 2
> France
> Tél:+33(0)4 77 42 83 36
> Fax:+33(0)4 77 42 66 66
> http://zimmer.aprilfoolsreview.com/
> 
> 

------------------------------------------------------------
IHMC                                     (850)434 8903 or (650)494 3973   
40 South Alcaniz St.           (850)202 4416   office
Pensacola                            (850)202 4440   fax
FL 32502                              (850)291 0667   mobile
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Received on Friday, 24 February 2012 17:03:51 UTC

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