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Re: xsd:duration (history) Re: Any objections against using xsd:anySimpleType or rdfs:Literal as the rdfs:range for OWL datatype properties?

From: Bob Ferris <zazi@elbklang.net>
Date: Sat, 25 Sep 2010 10:14:37 +0200
Message-ID: <4C9DAF6D.9030003@elbklang.net>
To: semantic-web@w3.org
Hi Jeremy,

thanks a lot for clarification. I wasn't aware of xs:dayTimeDuration 
from [3]. However, in a separate discussion with Alan Ruttenberg, I 
propsed also a range like it is defined for xs:dayTimeDuration:

 > As far as I understand the problem (I found more or less only the
 > statement "does not have a well-defined value space"[1] and had a
 > look at the value space definition of xsd:duration[2]), I would guess 
 > a duration representation that only includes days, hours, minutes,
 > and seconds can be appropriated for reasoning tasks?

;)

Am 25.09.2010 00:57, schrieb Jeremy Carroll:
> Hi Bob
>
> I did the work that excluded xsd:duration.
>
> The problem is the XML Schema group were under time pressure and had to
> go to press before they had really finished.
> An unresolved issue was to do with questions like how many days in a
> month, or how many seconds in an hour?
>
> These issues were addressed in XPath2 I think
> http://www.w3.org/2007/xpath-datatypes
> http://www.w3.org/TR/xpath-datamodel/
> Appendix C in particular
> and
> http://www.w3.org/TR/xpath-datamodel/#types-predefined
>
> These documents post-date the RDF and OWL1 recs that are the source of
> the exclusion.
>
> OWL in particular requires that you can tell whether two literal values
> are or are not the same.
> The duration datatype available in 2004 did not have that property.
>
> If these two duration datatypes are not in OWL2, personally I would
> regard that as a defect.

So yes, I would also vote to include at least xs:dayTimeDuration, 
because the units of day, hour, minute and second and their relations 
are well defined (from a general point of view).
Maybe, they didn't include it, because xs:dayTimeDuration is not a part 
of of XML Schema.

Cheers,


Bob

[1] http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#dtype_interp
[2] http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#duration
[3] http://www.w3.org/TR/xpath-datamodel/#types-predefined
Received on Saturday, 25 September 2010 08:15:13 GMT

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