RE: SSFS & Direct Semantics clarification: Invalid or inconsistent literals

Hello,

If an FS ontology document contains a literal such as "1.5"^^xsd:integer, then
it is syntactically incorrect. This is so because of the following facts:

(a) "1.5" is not a lexical value for xsd:integer (as specified in XML Schema).
(b) The FS ontology document can be parsed into an instance of the Ontology UML
class from the structural specification; however, because of (a), the parsed
instance of the Literal UML class does not satisfy the MUST restriction from
Section 5.7 ("The lexical form MUST conform to restrictions of the datatype
[...]").

I completely agree with the suggested rewording. I've added it to the document
and here is the diff:

http://www.w3.org/2007/OWL/wiki/index.php?title=Syntax&diff=24603&oldid=24489

Thanks a lot for this comment!

Regards,

	Boris 

> -----Original Message-----
> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] On
> Behalf Of Mike Smith
> Sent: 12 June 2009 17:33
> To: W3C OWL Working Group
> Cc: Birte Glimm
> Subject: SSFS & Direct Semantics clarification: Invalid or inconsistent
> literals
> 
> I am trying to resolve ambiguity with respect to literals for which
> the lexical value is not permitted by the datatype.  E.g.,
> 
> "string"^^xsd:decimal
> "1.5"^^xsd:integer
> 
> The question is whether such literals are (1) prohibited by the
> structural specification or (2) inconsistent according to the Direct
> Semantics.
> 
> I find (2) to be more intuitive and I think it more closely aligns
> with the RDF Based Semantics (to which I defer to Michael Schneider).
> But...
> 
> I believe that the intent of the current specifications is (1).  SSFS,
> section 5.7 says "The lexical form MUST conform to restrictions of the
> datatype, and it is mapped to a data value as specified by the
> datatype." And in the Direct Semantics document, the literal
> interpretation function is undefined for such literals.
> 
> If (1) is correct, then I suggest rewording the quoted sentence to
> remove confusion due to the phrase "restrictions of the datatype".
> E.g., I believe the following is less ambiguous and reuses the wording
> from the definition of datatype map.
> 
> "The lexical form MUST be an element of the lexical space of the
> datatype, and it is mapped to a data value as specified by the
> datatype."
> 
> 
> If (2) is correct, then the quoted sentence should be removed and the
> Direct Semantics should be extended to handle this case (which I
> believe would be a relatively minor change).
> 
> 
> --
> Mike Smith
> 
> Clark & Parsia

Received on Friday, 12 June 2009 16:52:21 UTC