W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > February 2002

Re: datatyping draft 3 (for telecon)

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Mon, 18 Feb 2002 13:13:06 -0600
Message-Id: <p0510140ab8970176223e@[65.212.118.219]>
To: Patrick Stickler <patrick.stickler@nokia.com>
Cc: w3c-rdfcore-wg@w3.org
>On 2002-02-15 23:39, "ext Pat Hayes" <phayes@ai.uwf.edu> wrote:
>
>>>  On Thu, 2002-02-14 at 22:58, Pat Hayes wrote:
>>>>   Latest version of the datatype summary document now available at
>>>>
>>>>   http://www.coginst.uwf.edu/users/phayes/DatatypeSummary3.html
>>>
>>>  Where's S-B?
>>>
>>>  i.e. what name are we giving to the class
>>>  of lexical representations of dates, so we can
>>>  use them in range constraints, ala...
>>>
>>>  dc:date rdfs:range rdfdt:date.lex.
>>>
>>>  _:work dc:date "2002-02-14".
>>
>>  As discussed, that  would be the rdf:range of a datatype property.
>>  I'll add comments about this in a version 4  tonight.
>
>I don't think so.
>
>My understanding about rdfs:range and general RDF classes is
>that, a non-datatype class is simply a value space.

Yes, although the adjective 'value' here is potentially misleading in 
this context. LIterals can be values in this sense.

>It's a set
>of values. And rdfs:range is a constraint on a property to
>have property values (statement objects) that are members of
>the value space (the only space) of the specified class.

Right.

>
>A datatype class (rdfs:Datatype) is a special kind of class

Yes, but here we are using the datatype as a property, rather than a 
class. Its the range of that property that Im  talking about.

>which, in addition to having the value space, the members
>of that value space have lexical representations, defined
>by an additional lexical space, and there is an N:1 mapping
>from the lexical space to the value space.

Right, and the datatype name used as a value denotes the inverse of 
that mapping.

>
>Thus, an rdfs:range constraint on a datatype class

Thats wouldn't mean anything; range constraints apply to properties, 
not classes.

>is no
>different than an rdfs:range constraint on a non-datatype
>class, it simply constrains to the value space of the class,
>whether it is datatype class is not relevant.

Well, except that being a datatype property, it is required to have 
the lexical space of the datatype as its range. That's part of the 
semantic requirements on a datatype property.

Pat

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Received on Monday, 18 February 2002 14:12:58 EST

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